Neural Control and Coordination - Comprehensive Question Paper

Section A: Multiple Choice Questions (MCQs) - 100 Questions (1 mark each)

1. The structural and functional unit of the nervous system is: a) Glial cell b) Neuron c) Axon d) Dendrite

2. Nissl's granules are found in: a) Axon b) Dendrites c) Cell body d) Myelin sheath

3. The region where axon emerges from cell body is called: a) Node of Ranvier b) Axon hillock c) Synapse d) Terminal bouton

4. Myelin sheath in PNS is formed by: a) Oligodendrocytes b) Astrocytes c) Schwann cells d) Microglia

5. Saltatory conduction occurs in: a) Unmyelinated axons b) Myelinated axons c) Dendrites d) Cell body

6. Multipolar neurons are most commonly found in: a) Retina b) Dorsal root ganglia c) Cerebral cortex d) Olfactory epithelium

7. Bipolar neurons are found in: a) Spinal cord b) Brain stem c) Retina d) Peripheral nerves

8. Sensory neurons are also called: a) Efferent neurons b) Afferent neurons c) Interneurons d) Motor neurons

9. The brain and spinal cord together form: a) PNS b) CNS c) ANS d) SNS

10. Cerebrospinal fluid is found in: a) Blood vessels b) Lymphatic system c) Meninges d) Muscles

11. The sympathetic nervous system prepares body for: a) Rest and digest b) Fight or flight c) Sleep d) Reproduction

12. Cranial nerves arise from: a) Spinal cord b) Brain c) Ganglia d) Muscles

13. Resting membrane potential is maintained by: a) Calcium pump b) Sodium-potassium pump c) Proton pump d) Glucose transporter

14. During depolarization, which channels open first? a) K+ channels b) Ca2+ channels c) Na+ channels d) Cl- channels

15. The refractory period ensures: a) Bidirectional impulse flow b) Unidirectional impulse flow c) No impulse flow d) Continuous impulse flow

16. Nodes of Ranvier are: a) Covered with myelin b) Gaps in myelin sheath c) Part of cell body d) Terminal buttons

17. The largest part of the brain is: a) Cerebellum b) Medulla c) Cerebrum d) Pons

18. The thalamus acts as: a) Motor center b) Relay station c) Respiratory center d) Cardiac center

19. Body temperature is regulated by: a) Thalamus b) Hypothalamus c) Cerebellum d) Medulla

20. The cerebral hemispheres are connected by: a) Pons b) Corpus callosum c) Medulla d) Thalamus

21. Corpora quadrigemina is located in: a) Forebrain b) Midbrain c) Hindbrain d) Spinal cord

22. Visual and auditory reflexes are controlled by: a) Cerebrum b) Cerebellum c) Corpora quadrigemina d) Medulla

23. Balance and coordination are controlled by: a) Cerebrum b) Cerebellum c) Medulla d) Pons

24. Vital functions like breathing are controlled by: a) Cerebrum b) Cerebellum c) Pons d) Medulla oblongata

25. A reflex action is: a) Voluntary and conscious b) Involuntary and unconscious c) Voluntary and unconscious d) Involuntary and conscious

26. The first component of reflex arc is: a) Effector b) Receptor c) Motor neuron d) Interneuron

27. Knee-jerk reflex is an example of: a) Polysynaptic reflex b) Monosynaptic reflex c) Conditioned reflex d) Learned reflex

28. In withdrawal reflex, the number of synapses involved is: a) One b) Two c) More than one d) Zero

29. Grey matter in brain consists of: a) Myelinated axons b) Cell bodies c) Only dendrites d) Only axons

30. White matter consists of: a) Cell bodies b) Dendrites c) Myelinated axons d) Unmyelinated axons

31. The protective covering of brain is called: a) Peritoneum b) Pleura c) Meninges d) Pericardium

32. Dura mater is the: a) Innermost meningeal layer b) Middle meningeal layer c) Outermost meningeal layer d) Only meningeal layer

33. Autonomic nervous system controls: a) Skeletal muscles b) Smooth muscles c) Voluntary actions d) Conscious movements

34. Parasympathetic nervous system promotes: a) Fight or flight b) Rest and digest c) Stress response d) Emergency response

35. Neurotransmitters are released from: a) Dendrites b) Cell body c) Axon terminals d) Nodes of Ranvier

36. The space between two neurons is called: a) Node b) Gap junction c) Synaptic cleft d) Axon hillock

37. Hyperpolarization occurs due to: a) Na+ influx b) K+ efflux c) Ca2+ influx d) Cl- efflux

38. Threshold potential is the: a) Resting potential b) Maximum potential c) Minimum potential for action potential d) Zero potential

39. Continuous conduction occurs in: a) Myelinated axons b) Unmyelinated axons c) Dendrites only d) Cell body only

40. Pseudounipolar neurons are found in: a) Brain b) Spinal cord c) Dorsal root ganglia d) Muscles

41. The outer layer of cerebrum is called: a) White matter b) Grey matter c) Cerebral cortex d) Corpus callosum

42. Pia mater is the: a) Outermost layer b) Middle layer c) Innermost layer d) Only layer of meninges

43. Arachnoid mater is located: a) Outside dura mater b) Between dura and pia mater c) Inside pia mater d) In spinal cord only

44. Spinal nerves are: a) Only sensory b) Only motor c) Mixed nerves d) Only autonomic

45. The number of spinal nerve pairs is: a) 12 b) 24 c) 31 d) 43

46. Cranial nerve pairs are: a) 10 b) 12 c) 24 d) 31

47. Somatic nervous system innervates: a) Heart b) Lungs c) Skeletal muscles d) Digestive system

48. Voluntary actions are controlled by: a) ANS b) SNS c) Sympathetic system d) Parasympathetic system

49. Involuntary actions are controlled by: a) SNS b) ANS c) Cerebrum d) Cerebellum

50. Ganglia are collections of: a) Axons b) Dendrites c) Cell bodies d) Synapses

51. Schwann cells are found in: a) CNS b) PNS c) Both CNS and PNS d) Neither CNS nor PNS

52. Oligodendrocytes are found in: a) PNS b) CNS c) Both CNS and PNS d) Neither CNS nor PNS

53. Telodendria are: a) Branched dendrites b) Branched axon terminals c) Cell body extensions d) Myelin segments

54. Synaptic knobs contain: a) Nucleus b) Mitochondria c) Neurotransmitters d) Ribosomes

55. The all-or-none principle applies to: a) Resting potential b) Graded potential c) Action potential d) Threshold potential

56. Sodium-potassium pump transports: a) 2 Na+ out, 3 K+ in b) 3 Na+ out, 2 K+ in c) Equal Na+ and K+ d) Only Na+ out

57. Repolarization is caused by: a) Na+ influx b) K+ efflux c) Ca2+ influx d) Cl- influx

58. The fastest nerve conduction occurs in: a) Unmyelinated thin axons b) Unmyelinated thick axons c) Myelinated thin axons d) Myelinated thick axons

59. Excitatory postsynaptic potential (EPSP) causes: a) Hyperpolarization b) Depolarization c) No change d) Repolarization

60. Inhibitory postsynaptic potential (IPSP) causes: a) Depolarization b) Hyperpolarization c) No change d) Action potential

61. The pons is part of: a) Forebrain b) Midbrain c) Hindbrain d) Spinal cord

62. Respiration and sleep are controlled by: a) Medulla b) Pons c) Cerebellum d) Thalamus

63. The brain stem includes: a) Cerebrum and cerebellum b) Midbrain, pons, and medulla c) Only medulla d) Thalamus and hypothalamus

64. Muscle tone is maintained by: a) Cerebrum b) Cerebellum c) Medulla d) Hypothalamus

65. Emotions are regulated by: a) Cerebellum b) Medulla c) Hypothalamus d) Pons

66. The stretch reflex involves: a) Multiple synapses b) Single synapse c) No synapses d) Only inhibitory synapses

67. Polysynaptic reflexes involve: a) Direct connection between sensory and motor neurons b) Interneurons c) Only motor neurons d) Only sensory neurons

68. Reflex time is: a) Very long b) Moderately long c) Very short d) Variable

69. Reflexes are processed in: a) Brain only b) Spinal cord only c) Both brain and spinal cord d) Muscles

70. Conditioned reflexes are: a) Inborn b) Learned c) Automatic d) Unconscious

71. Unconditioned reflexes are: a) Learned b) Inborn c) Voluntary d) Conscious

72. The effector in reflex arc can be: a) Only muscle b) Only gland c) Both muscle and gland d) Only nerve

73. Sensory receptors convert: a) Electrical energy to mechanical b) Mechanical energy to electrical c) Chemical energy to heat d) Light to sound

74. Motor neurons innervate: a) Only skeletal muscle b) Only smooth muscle c) Only cardiac muscle d) All types of muscles

75. Interneurons are found in: a) PNS only b) CNS only c) Both CNS and PNS d) Muscles

76. The cell body of sensory neurons is located in: a) CNS b) Ganglia c) Muscles d) Glands

77. The cell body of motor neurons is located in: a) Ganglia b) CNS c) Muscles d) Receptors

78. Afferent pathways carry impulses: a) Away from CNS b) Towards CNS c) Within CNS only d) Between muscles

79. Efferent pathways carry impulses: a) Towards CNS b) Away from CNS c) Within CNS only d) Between receptors

80. Integration of information occurs in: a) Receptors b) Effectors c) CNS d) PNS

81. The longest cells in human body are: a) Muscle cells b) Nerve cells c) Bone cells d) Blood cells

82. Nerve impulses travel at speeds up to: a) 1 m/s b) 10 m/s c) 100 m/s d) 1000 m/s

83. The resting potential of a neuron is approximately: a) +70 mV b) -70 mV c) 0 mV d) +35 mV

84. Action potential peak is approximately: a) -70 mV b) 0 mV c) +30 mV d) +70 mV

85. Calcium ions are important for: a) Resting potential b) Action potential c) Neurotransmitter release d) Myelin formation

86. Acetylcholine is a: a) Hormone b) Enzyme c) Neurotransmitter d) Structural protein

87. The blood-brain barrier is formed by: a) Neurons b) Glial cells c) Blood vessels d) Meninges

88. Glial cells function to: a) Conduct impulses b) Support neurons c) Contract muscles d) Secrete hormones

89. Multiple sclerosis affects: a) Cell bodies b) Dendrites c) Myelin sheath d) Synapses

90. Parkinson's disease affects: a) Sensory neurons b) Motor neurons c) Dopamine-producing neurons d) All neurons

91. Alzheimer's disease primarily affects: a) Spinal cord b) Brain c) Peripheral nerves d) Muscles

92. Epilepsy is characterized by: a) Loss of neurons b) Abnormal electrical activity c) Loss of myelin d) Blocked synapses

93. Stroke occurs due to: a) Nerve damage b) Muscle weakness c) Blood supply disruption to brain d) Hormone imbalance

94. Paralysis can result from damage to: a) Sensory neurons only b) Motor neurons only c) Interneurons only d) Any type of neurons

95. Numbness indicates damage to: a) Motor neurons b) Sensory neurons c) Interneurons d) Muscles

96. Local anesthetics work by: a) Enhancing nerve conduction b) Blocking nerve conduction c) Accelerating synapses d) Increasing neurotransmitters

97. Caffeine affects the nervous system by: a) Blocking receptors b) Stimulating neurons c) Destroying synapses d) Reducing blood flow

98. Alcohol affects the nervous system by: a) Stimulating all neurons b) Depressing CNS function c) Enhancing reflexes d) Improving memory

99. The nervous system develops from: a) Mesoderm b) Endoderm c) Ectoderm d) All germ layers

100. Neuroplasticity refers to: a) Physical flexibility of neurons b) Ability of nervous system to reorganize c) Neuron multiplication d) Nerve regeneration only

Section B: Short Answer Questions (1 mark each) - 100 Questions

1. Define a neuron.
2. Name the three main parts of a neuron.
3. What are Nissl's granules?
4. Define axon hillock.
5. What is myelin sheath?
6. Name the cells that form myelin in PNS.
7. What are Nodes of Ranvier?
8. Define saltatory conduction.
9. What is the difference between multipolar and bipolar neurons?
10. Name the three functional types of neurons.
11. What does CNS stand for?
12. What does PNS stand for?
13. List the two main divisions of PNS.
14. What is the autonomic nervous system?
15. Define resting membrane potential.
16. What maintains the resting membrane potential?
17. Define threshold potential.
18. What happens during depolarization?
19. What is repolarization?
20. Define refractory period.
21. Name the largest part of the brain.
22. What connects the two cerebral hemispheres?
23. What is the function of thalamus?
24. Where is the hypothalamus located?
25. Name the three parts of hindbrain.
26. What is the function of cerebellum?
27. Which part of brain controls breathing?
28. Define reflex action.
29. List the components of a reflex arc.
30. What is a monosynaptic reflex?
31. Give an example of monosynaptic reflex.
32. What is a polysynaptic reflex?
33. Name the three meningeal layers.
34. What is cerebrospinal fluid?
35. Define synapse.
36. What are neurotransmitters?
37. Where are neurotransmitters stored?
38. What is synaptic cleft?
39. Define grey matter.
40. Define white matter.
41. What are dendrites?
42. Function of dendrites.
43. What is an axon?
44. Function of axons.
45. What are telodendria?
46. Define ganglia.
47. What are Schwann cells?
48. What are oligodendrocytes?
49. Name a common neurotransmitter.
50. What is continuous conduction?
51. Define unipolar neuron.
52. Where are bipolar neurons found?
53. What are interneurons?
54. Function of sensory neurons.
55. Function of motor neurons.
56. What is sympathetic nervous system?
57. What is parasympathetic nervous system?
58. How many pairs of cranial nerves are there?
59. How many pairs of spinal nerves are there?
60. What is somatic nervous system?
61. Define effector organ.
62. What is a receptor?
63. Name the ion responsible for depolarization.
64. Name the ion responsible for repolarization.
65. What is action potential?
66. Define nerve impulse.
67. What is the all-or-none principle?
68. What causes hyperpolarization?
69. What are voltage-gated channels?
70. Define excitatory synapse.
71. Define inhibitory synapse.
72. What is EPSP?
73. What is IPSP?
74. Name the middle layer of meninges.
75. What is the function of medulla oblongata?
76. What are corpora quadrigemina?
77. Where is the midbrain located?
78. What connects forebrain and hindbrain?
79. Function of pons.
80. What is cerebral cortex?
81. Define reflex arc.
82. What is reflex time?
83. Are reflexes voluntary or involuntary?
84. What is withdrawal reflex?
85. Name the outermost meningeal layer.
86. Name the innermost meningeal layer.
87. What protects the CNS?
88. Function of CSF.
89. What is blood-brain barrier?
90. Define glial cells.
91. What is neuroplasticity?
92. Name a disease affecting myelin.
93. What causes paralysis?
94. What causes numbness?
95. How does local anesthesia work?
96. What is the effect of alcohol on nervous system?
97. From which germ layer does nervous system develop?
98. What is the fastest type of nerve fiber?
99. What is the slowest type of nerve fiber?
100. Define integration in nervous system.

Section C: Short Answer Questions (2 marks each) - 100 Questions

1. Describe the structure of a typical neuron with a labeled diagram.
2. Explain the difference between myelinated and unmyelinated axons.
3. Compare multipolar, bipolar, and unipolar neurons.
4. Differentiate between sensory, motor, and interneurons.
5. Explain the organization of the nervous system into CNS and PNS.
6. Describe the subdivisions of the peripheral nervous system.
7. Compare sympathetic and parasympathetic nervous systems.
8. Explain the mechanism of maintaining resting membrane potential.
9. Describe the process of depolarization in nerve impulse transmission.
10. Explain repolarization and hyperpolarization phases.
11. Compare continuous and saltatory conduction.
12. Describe the structure and function of a synapse.
13. Explain synaptic transmission of nerve impulses.
14. List the major parts of forebrain and their functions.
15. Describe the structure and function of midbrain.
16. List the parts of hindbrain and their main functions.
17. Explain the protective coverings of the brain.
18. Describe the formation and circulation of cerebrospinal fluid.
19. Draw and label a typical reflex arc.
20. Compare monosynaptic and polysynaptic reflexes with examples.
21. Explain the knee-jerk reflex mechanism.
22. Describe the withdrawal reflex pathway.
23. Compare voluntary and involuntary actions.
24. Explain the role of hypothalamus in homeostasis.
25. Describe the function of cerebellum in motor control.
26. Compare grey matter and white matter in CNS.
27. Explain the blood-brain barrier and its significance.
28. Describe the types of glial cells and their functions.
29. Compare afferent and efferent pathways.
30. Explain the all-or-none principle of nerve impulse.
31. Describe the refractory period and its importance.
32. Compare excitatory and inhibitory synapses.
33. Explain EPSP and IPSP with their significance.
34. Describe the role of calcium ions in synaptic transmission.
35. Compare cranial and spinal nerves.
36. Explain the organization of autonomic nervous system.
37. Describe the fight-or-flight response.
38. Explain the rest-and-digest response.
39. Compare somatic and autonomic nervous systems.
40. Describe the structure of spinal cord.
41. Explain ascending and descending tracts in spinal cord.
42. Describe the meningeal layers and their functions.
43. Explain the significance of Nodes of Ranvier.
44. Compare pseudounipolar and unipolar neurons.
45. Describe the cellular components of nervous tissue.
46. Explain the development of nervous system.
47. Compare motor and sensory areas of cerebral cortex.
48. Describe the limbic system and its functions.
49. Explain the reticular formation and its role.
50. Compare slow and fast nerve fibers.
51. Describe neuromuscular junction.
52. Explain the mechanism of muscle contraction control.
53. Compare skeletal, smooth, and cardiac muscle innervation.
54. Describe pain pathways in nervous system.
55. Explain referred pain mechanism.
56. Compare acute and chronic pain.
57. Describe the gate control theory of pain.
58. Explain endogenous pain control mechanisms.
59. Compare sensory and motor homunculus.
60. Describe brain waves and their significance.
61. Explain sleep-wake cycle regulation.
62. Compare REM and NREM sleep.
63. Describe circadian rhythm control.
64. Explain memory formation and types.
65. Compare short-term and long-term memory.
66. Describe learning mechanisms in brain.
67. Explain habituation and sensitization.
68. Compare classical and operant conditioning.
69. Describe language areas in brain.
70. Explain lateralization of brain functions.
71. Compare Broca's and Wernicke's areas.
72. Describe motor learning and skill acquisition.
73. Explain plasticity in developing nervous system.
74. Compare regeneration in CNS and PNS.
75. Describe common neurodegenerative diseases.
76. Explain multiple sclerosis pathophysiology.
77. Compare Parkinson's and Alzheimer's diseases.
78. Describe epilepsy and its types.
79. Explain stroke types and consequences.
80. Compare spinal cord injuries and their effects.
81. Describe traumatic brain injury classifications.
82. Explain concussion and its effects.
83. Compare sensory and motor deficits.
84. Describe rehabilitation principles in neurological disorders.
85. Explain neuroimaging techniques.
86. Compare CT and MRI in brain imaging.
87. Describe EEG and its applications.
88. Explain nerve conduction studies.
89. Compare local and general anesthetics.
90. Describe analgesic mechanisms.
91. Explain neurotoxins and their effects.
92. Compare stimulants and depressants.
93. Describe addiction mechanisms in brain.
94. Explain tolerance and withdrawal.
95. Compare neurological and psychiatric disorders.
96. Describe stress response pathways.
97. Explain psychosomatic disorders.
98. Compare acute and chronic stress effects.
99. Describe meditation effects on brain.
100. Explain exercise benefits for nervous system.

Section D: Long Answer Questions (3 marks each) - 100 Questions

1. Draw a detailed diagram of a neuron and explain the function of each part in nerve impulse transmission.
2. Describe the classification of neurons based on structure and function with suitable examples.
3. Explain the detailed mechanism of nerve impulse conduction along a myelinated axon.
4. Compare and contrast the organization and functions of central and peripheral nervous systems.
5. Describe the autonomic nervous system with its subdivisions and their contrasting effects on body organs.
6. Explain the ionic basis of resting membrane potential and action potential generation.
7. Describe synaptic transmission including the role of neurotransmitters and synaptic integration.
8. Draw a detailed diagram of human brain and explain the functions of its major parts.
9. Explain the concept of reflex action with detailed description of monosynaptic and polysynaptic reflexes.
10. Describe the protective mechanisms of the central nervous system including meninges and CSF.
11. Explain the development of nervous system from neural tube with major developmental milestones.
12. Describe the cellular organization of nervous tissue including neurons and glial cells.
13. Explain the functional organization of cerebral cortex with motor and sensory areas.
14. Describe the role of hypothalamus in maintaining homeostasis and endocrine regulation.
15. Explain the structure and function of cerebellum in motor control and balance.
16. Describe the brain stem and its vital functions in maintaining life processes.
17. Explain the mechanism of pain perception and modulation in the nervous system.
18. Describe the neural basis of memory formation, storage, and retrieval.
19. Explain the sleep-wake cycle regulation and the role of circadian rhythms.
20. Describe the neural control of voluntary and involuntary movements.
21. Explain the sensory pathways from receptors to cerebral cortex.
22. Describe the motor pathways from cerebral cortex to muscles.
23. Explain the integration of sensory and motor functions in spinal cord.
24. Describe the cranial nerves with their origins, courses, and functions.
25. Explain the formation, circulation, and functions of cerebrospinal fluid.
26. Describe the blood-brain barrier, its structure, and physiological significance.
27. Explain the process of myelination and its importance in nerve conduction.
28. Describe the neuromuscular junction and mechanism of muscle contraction control.
29. Explain the neural control of breathing and cardiovascular functions.
30. Describe the limbic system and its role in emotions and behavior.
31. Explain the reticular formation and its functions in consciousness and arousal.
32. Describe the visual pathway from eye to visual cortex.
33. Explain the auditory pathway from ear to auditory cortex.
34. Describe the gustatory and olfactory pathways.
35. Explain the somatosensory pathways for touch, temperature, and pain.
36. Describe the proprioceptive pathways and their role in body awareness.
37. Explain the vestibular system and its role in balance and spatial orientation.
38. Describe the neural control of digestive system functions.
39. Explain the neural regulation of body temperature.
40. Describe the neural control of urinary system functions.
41. Explain the neural basis of reproductive behavior and hormonal control.
42. Describe the stress response pathways and their physiological effects.
43. Explain the neural mechanisms of addiction and tolerance.
44. Describe the effects of various drugs on nervous system function.
45. Explain the neural basis of learning and conditioning.
46. Describe the development of language areas and speech control.
47. Explain the lateralization of brain functions and hemispheric specialization.
48. Describe the neural plasticity and its role in recovery from brain injury.
49. Explain the aging process in nervous system and its consequences.
50. Describe the common neurodegenerative diseases and their pathophysiology.
51. Explain multiple sclerosis as an autoimmune disorder affecting myelin.
52. Describe Parkinson's disease and its effects on motor control.
53. Explain Alzheimer's disease and its impact on memory and cognition.
54. Describe epilepsy, its types, and underlying mechanisms.
55. Explain stroke types, risk factors, and neurological consequences.
56. Describe spinal cord injuries and their classification based on level and completeness.
57. Explain traumatic brain injury and its acute and chronic effects.
58. Describe the principles of neurorehabilitation and recovery mechanisms.
59. Explain the diagnostic techniques used in neurology.
60. Describe the electroencephalography and its clinical applications.
61. Explain neuroimaging techniques and their uses in diagnosis.
62. Describe nerve conduction studies and electromyography.
63. Explain the lumbar puncture procedure and CSF analysis.
64. Describe the mechanisms of action of local anesthetics.
65. Explain general anesthesia and its effects on consciousness.
66. Describe analgesic drugs and their mechanisms of pain relief.
67. Explain anticonvulsant drugs and their use in epilepsy treatment.
68. Describe antiparkinsonian drugs and dopamine replacement therapy.
69. Explain psychoactive drugs and their effects on neurotransmission.
70. Describe antidepressants and their mechanisms of action.
71. Explain anxiolytic drugs and their effects on GABA transmission.
72. Describe stimulants and their effects on arousal and attention.
73. Explain the neurotoxic effects of alcohol on nervous system.
74. Describe the effects of caffeine and nicotine on brain function.
75. Explain the neural mechanisms of circadian rhythm disorders.
76. Describe sleep disorders and their neurological basis.
77. Explain attention deficit hyperactivity disorder (ADHD) and its neural basis.
78. Describe autism spectrum disorders and their neurological features.
79. Explain schizophrenia and its neurobiological aspects.
80. Describe depression and its neurochemical basis.
81. Explain anxiety disorders and their neural substrates.
82. Describe post-traumatic stress disorder and its brain changes.
83. Explain the neural basis of personality disorders.
84. Describe the effects of meditation on brain structure and function.
85. Explain the benefits of physical exercise for nervous system health.
86. Describe the role of nutrition in maintaining nervous system function.
87. Explain the effects of environmental toxins on nervous system development.
88. Describe the neural mechanisms of chronic pain syndromes.
89. Explain phantom limb pain and its neurological basis.
90. Describe migraine headaches and their neural mechanisms.
91. Explain the neural control of immune system function.
92. Describe the gut-brain axis and its physiological significance.
93. Explain the neural mechanisms of appetite and weight regulation.
94. Describe the role of nervous system in thermal regulation.
95. Explain the neural control of water and electrolyte balance.
96. Describe the integration of nervous and endocrine systems in maintaining homeostasis.
97. Explain the neural mechanisms underlying consciousness and awareness.
98. Describe the evolutionary development of nervous system complexity across species.
99. Explain the role of glial cells in supporting neuronal function and brain health.
100. Describe the future directions in neuroscience research and potential therapeutic applications.

---

Answer Key Guidelines

Section A: Multiple Choice Questions (MCQs) - Answers

1. b) Neuron
2. c) Cell body
3. b) Axon hillock
4. c) Schwann cells
5. b) Myelinated axons
6. c) Cerebral cortex
7. c) Retina
8. b) Afferent neurons
9. b) CNS
10. c) Meninges
11. b) Fight or flight
12. b) Brain
13. b) Sodium-potassium pump
14. c) Na+ channels
15. b) Unidirectional impulse flow
16. b) Gaps in myelin sheath
17. c) Cerebrum
18. b) Relay station
19. b) Hypothalamus
20. b) Corpus callosum
21. b) Midbrain
22. c) Corpora quadrigemina
23. b) Cerebellum
24. d) Medulla oblongata
25. b) Involuntary and unconscious
26. b) Receptor
27. b) Monosynaptic reflex
28. c) More than one
29. b) Cell bodies
30. c) Myelinated axons
31. c) Meninges
32. c) Outermost meningeal layer
33. b) Smooth muscles
34. b) Rest and digest
35. c) Axon terminals
36. c) Synaptic cleft
37. b) K+ efflux
38. c) Minimum potential for action potential
39. b) Unmyelinated axons
40. c) Dorsal root ganglia
41. c) Cerebral cortex
42. c) Innermost layer
43. b) Between dura and pia mater
44. c) Mixed nerves
45. c) 31
46. b) 12
47. c) Skeletal muscles
48. b) SNS
49. b) ANS
50. c) Cell bodies
51. b) PNS
52. b) CNS
53. b) Branched axon terminals
54. c) Neurotransmitters
55. c) Action potential
56. b) 3 Na+ out, 2 K+ in
57. b) K+ efflux
58. d) Myelinated thick axons
59. b) Depolarization
60. b) Hyperpolarization
61. c) Hindbrain
62. b) Pons
63. b) Midbrain, pons, and medulla
64. b) Cerebellum
65. c) Hypothalamus
66. b) Single synapse
67. b) Interneurons
68. c) Very short
69. c) Both brain and spinal cord
70. b) Learned
71. b) Inborn
72. c) Both muscle and gland
73. b) Mechanical energy to electrical
74. d) All types of muscles
75. b) CNS only
76. b) Ganglia
77. b) CNS
78. b) Towards CNS
79. b) Away from CNS
80. c) CNS
81. b) Nerve cells
82. c) 100 m/s
83. b) -70 mV
84. c) +30 mV
85. c) Neurotransmitter release
86. c) Neurotransmitter
87. b) Glial cells
88. b) Support neurons
89. c) Myelin sheath
90. c) Dopamine-producing neurons
91. b) Brain
92. b) Abnormal electrical activity
93. c) Blood supply disruption to brain
94. b) Motor neurons only
95. b) Sensory neurons
96. b) Blocking nerve conduction
97. b) Stimulating neurons
98. b) Depressing CNS function
99. c) Ectoderm
100. b) Ability of nervous system to reorganize

Section B: Short Answer Questions (1 mark each) - Answers

1. Define a neuron. A neuron is the structural and functional unit of the nervous system, specialized to transmit electrical signals called nerve impulses.

2. Name the three main parts of a neuron. Cell body (soma), dendrites, and axon.

3. What are Nissl's granules? Nissl's granules are rough endoplasmic reticulum and free ribosomes found in the cell body of neurons, involved in protein synthesis.

4. Define axon hillock. The axon hillock is the region where the axon emerges from the cell body.

5. What is myelin sheath? A fatty insulating layer covering many axons that speeds up nerve impulse conduction.

6. Name the cells that form myelin in PNS. Schwann cells.

7. What are Nodes of Ranvier? Gaps in the myelin sheath along the axon where the nerve impulse jumps from node to node.

8. Define saltatory conduction. The jumping of nerve impulses from one Node of Ranvier to the next in myelinated axons, significantly increasing conduction speed.

9. What is the difference between multipolar and bipolar neurons? Multipolar neurons have one axon and two or more dendrites (e.g., cerebral cortex). Bipolar neurons have one axon and one dendrite (e.g., retina).

10. Name the three functional types of neurons. Sensory (afferent), motor (efferent), and interneurons (association neurons).

11. What does CNS stand for? Central Nervous System.

12. What does PNS stand for? Peripheral Nervous System.

13. List the two main divisions of PNS. Somatic Nervous System (SNS) and Autonomic Nervous System (ANS).

14. What is the autonomic nervous system? The ANS controls involuntary functions of internal organs (e.g., heart rate, digestion).

15. Define resting membrane potential. The electrical potential difference across the membrane of a resting neuron, with the inside being negatively charged relative to the outside.

16. What maintains the resting membrane potential? The sodium-potassium pump and differential membrane permeability to Na+ and K+ ions.

17. Define threshold potential. The minimum potential required for voltage-gated Na+ channels to open and initiate an action potential.

18. What happens during depolarization? Voltage-gated Na+ channels open, allowing Na+ ions to rush into the cell, making the inside of the membrane less negative (more positive).

19. What is repolarization? Voltage-gated Na+ channels inactivate and K+ channels open, allowing K+ ions to rush out, making the inside of the membrane negative again.

20. Define refractory period. A brief period after an action potential during which the neuron is less responsive to further stimulation, ensuring unidirectional impulse flow.

21. Name the largest part of the brain. Cerebrum.

22. What connects the two cerebral hemispheres? Corpus callosum.

23. What is the function of thalamus? A major relay station for sensory impulses (except smell) to the cerebral cortex.

24. Where is the hypothalamus located? At the base of the thalamus.

25. Name the three parts of hindbrain. Pons, cerebellum, and medulla oblongata.

26. What is the function of cerebellum? Coordinates voluntary movements, maintains posture, balance, and muscle tone.

27. Which part of brain controls breathing? Medulla oblongata.

28. Define reflex action. A rapid, involuntary, and unconscious response to a stimulus.

29. List the components of a reflex arc. Receptor, afferent neuron, interneuron, efferent neuron, and effector.

30. What is a monosynaptic reflex? A reflex arc involving only one synapse between the sensory and motor neuron (no interneuron).

31. Give an example of monosynaptic reflex. Knee-jerk reflex.

32. What is a polysynaptic reflex? A reflex arc involving more than one synapse and an interneuron.

33. Name the three meningeal layers. Dura mater, arachnoid mater, and pia mater.

34. What is cerebrospinal fluid? A fluid that protects the brain and spinal cord, providing cushioning and nutrient transport.

35. Define synapse. The junction between two neurons where nerve impulses are transmitted.

36. What are neurotransmitters? Chemicals released at axon terminals that transmit signals across the synaptic cleft to another neuron or effector.

37. Where are neurotransmitters stored? In synaptic knobs (boutons) within vesicles.

38. What is synaptic cleft? The space between the axon terminal of one neuron and the dendrite/cell body of another neuron.

39. Define grey matter. Regions of the CNS primarily composed of neuronal cell bodies, dendrites, unmyelinated axons, and glial cells.

40. Define white matter. Regions of the CNS primarily composed of myelinated axons.

41. What are dendrites? Short, branched processes extending from the cell body that receive nerve impulses from other neurons.

42. Function of dendrites. Receive nerve impulses from other neurons and transmit them towards the cell body.

43. What is an axon? A single, long projection extending from the cell body that transmits nerve impulses away from the cell body.

44. Function of axons. Transmit nerve impulses away from the cell body to other neurons, muscles, or glands.

45. What are telodendria? The terminal branches of an axon, ending in synaptic knobs.

46. Define ganglia. Collections of neuronal cell bodies located outside the CNS.

47. What are Schwann cells? Glial cells that form the myelin sheath around axons in the Peripheral Nervous System (PNS).

48. What are oligodendrocytes? Glial cells that form the myelin sheath around axons in the Central Nervous System (CNS).

49. Name a common neurotransmitter. Acetylcholine (or dopamine, serotonin, etc.).

50. What is continuous conduction? The continuous propagation of a nerve impulse along the entire length of an unmyelinated axon.

51. Define unipolar neuron. A neuron with a single process extending from the cell body, which then divides into an axonal and a dendritic branch.

52. Where are bipolar neurons found? In the retina of the eye and olfactory epithelium.

53. What are interneurons? Neurons located entirely within the CNS that connect sensory and motor neurons, integrating information.

54. Function of sensory neurons. Transmit impulses from sensory receptors towards the CNS.

55. Function of motor neurons. Transmit impulses from the CNS to effector organs (muscles or glands).

56. What is sympathetic nervous system? A division of the ANS that prepares the body for "fight or flight" responses.

57. What is parasympathetic nervous system? A division of the ANS that promotes "rest and digest" activities.

58. How many pairs of cranial nerves are there? 12 pairs.

59. How many pairs of spinal nerves are there? 31 pairs.

60. What is somatic nervous system? A division of the PNS that controls voluntary movements by transmitting signals to skeletal muscles.

61. Define effector organ. A muscle or gland that responds to a motor impulse.

62. What is a receptor? A specialized structure that detects a stimulus.

63. Name the ion responsible for depolarization. Sodium (Na+).

64. Name the ion responsible for repolarization. Potassium (K+).

65. What is action potential? An electrical signal (nerve impulse) that travels along the neuron's membrane.

66. Define nerve impulse. An electrical signal transmitted along a nerve fiber in response to a stimulus.

67. What is the all-or-none principle? An action potential either fires completely or not at all; its strength is independent of the stimulus intensity once threshold is reached.

68. What causes hyperpolarization? Slow closing of K+ channels, leading to a brief period where the membrane potential becomes more negative than the resting potential.

69. What are voltage-gated channels? Ion channels that open or close in response to changes in membrane potential.

70. Define excitatory synapse. A synapse where the neurotransmitter causes depolarization of the postsynaptic membrane, making it more likely to fire an action potential.

71. Define inhibitory synapse. A synapse where the neurotransmitter causes hyperpolarization of the postsynaptic membrane, making it less likely to fire an action potential.

72. What is EPSP? Excitatory Postsynaptic Potential: A temporary depolarization of the postsynaptic membrane caused by excitatory neurotransmitters.

73. What is IPSP? Inhibitory Postsynaptic Potential: A temporary hyperpolarization of the postsynaptic membrane caused by inhibitory neurotransmitters.

74. Name the middle layer of meninges. Arachnoid mater.

75. What is the function of medulla oblongata? Controls vital involuntary functions like breathing, heart rate, blood pressure, swallowing, and vomiting.

76. What are corpora quadrigemina? Four rounded swellings in the midbrain involved in visual and auditory reflexes.

77. Where is the midbrain located? Between the thalamus/hypothalamus and the pons.

78. What connects forebrain and hindbrain? Midbrain.

79. Function of pons. A bridge of nerve fibers connecting different brain regions, involved in respiration and sleep.

80. What is cerebral cortex? The outer layer of the cerebrum (grey matter), responsible for higher cognitive functions.

81. Define reflex arc. The neural pathway that mediates a reflex action.

82. What is reflex time? The time taken for a reflex action to occur from stimulus to response.

83. Are reflexes voluntary or involuntary? Involuntary.

84. What is withdrawal reflex? A polysynaptic reflex that causes rapid withdrawal of a limb from a painful stimulus.

85. Name the outermost meningeal layer. Dura mater.

86. Name the innermost meningeal layer. Pia mater.

87. What protects the CNS? Meninges and cerebrospinal fluid (CSF).

88. Function of CSF. Cushions the brain and spinal cord, provides nutrients, and removes waste.

89. What is blood-brain barrier? A protective mechanism that regulates the passage of substances from the blood into the brain.

90. Define glial cells. Non-neuronal cells in the nervous system that support, nourish, and protect neurons.

91. What is neuroplasticity? The ability of the nervous system to change and reorganize its structure and function in response to experience.

92. Name a disease affecting myelin. Multiple Sclerosis.

93. What causes paralysis? Damage to motor neurons or pathways that prevent muscle movement.

94. What causes numbness? Damage to sensory neurons or pathways that impair sensation.

95. How does local anesthesia work? By blocking nerve conduction, preventing pain signals from reaching the brain.

96. What is the effect of alcohol on nervous system? It depresses CNS function, leading to impaired coordination, judgment, and slowed reactions.

97. From which germ layer does nervous system develop? Ectoderm.

98. What is the fastest type of nerve fiber? Myelinated thick axons.

99. What is the slowest type of nerve fiber? Unmyelinated thin axons.

100. Define integration in nervous system. The process by which the CNS combines and processes sensory information to make decisions and initiate responses.

Answers for Section C: Short Answer Questions (2 marks each)

Here are the answers to the questions in Section C, based on the provided document "5.5_Neural_Control_and_Coordination.md".

1. Describe the structure of a typical neuron with a labeled diagram. A typical neuron consists of three main parts:

• Cell Body (Soma): Contains the nucleus, cytoplasm, and characteristic Nissl's granules involved in protein synthesis. It is the metabolic center of the neuron.
• Dendrites: Short, branched processes that receive signals from other neurons and transmit them towards the cell body.
• Axon: A single, long projection that transmits nerve impulses away from the cell body to other neurons or effectors. It ends in axon terminals with synaptic knobs.

2. Explain the difference between myelinated and unmyelinated axons.

• Myelinated Axons: Are covered by a fatty myelin sheath, which acts as an insulator. This sheath has gaps called Nodes of Ranvier. Impulses jump from node to node (saltatory conduction), which is very fast.
• Unmyelinated Axons: Lack a myelin sheath. The nerve impulse travels continuously along the entire axon membrane, which is a slower process (continuous conduction).

3. Compare multipolar, bipolar, and unipolar neurons.

• Multipolar: Have one axon and multiple dendrites. They are the most common type, found in the cerebral cortex.
• Bipolar: Have one axon and one dendrite. They are found in specialized sensory organs like the retina of the eye.
• Unipolar: Have a single process that extends from the cell body and then splits into an axon and a dendrite. They are found in the dorsal root ganglia of spinal nerves.

4. Differentiate between sensory, motor, and interneurons.

• Sensory (Afferent) Neurons: Transmit impulses from sensory receptors (e.g., skin) to the Central Nervous System (CNS).
• Motor (Efferent) Neurons: Transmit impulses from the CNS to effector organs like muscles or glands.
• Interneurons: Are located entirely within the CNS and act as connectors, integrating information between sensory and motor neurons.

5. Explain the organization of the nervous system into CNS and PNS. The nervous system is divided into two main parts:

• Central Nervous System (CNS): This is the primary processing center and includes the brain and spinal cord.
• Peripheral Nervous System (PNS): This consists of all the nerves that extend from the CNS to the rest of the body, including cranial nerves from the brain and spinal nerves from the spinal cord. It connects the CNS to the limbs and organs.

6. Describe the subdivisions of the peripheral nervous system. The PNS is subdivided into:

• Somatic Nervous System (SNS): Controls voluntary actions by relaying signals from the CNS to skeletal muscles.
• Autonomic Nervous System (ANS): Controls involuntary functions of internal organs. It is further divided into the Sympathetic and Parasympathetic systems.

7. Compare sympathetic and parasympathetic nervous systems.

• Sympathetic Nervous System: Prepares the body for "fight or flight" responses. It increases heart rate, dilates pupils, and readies the body for action.
• Parasympathetic Nervous System: Promotes "rest and digest" activities. It slows the heart rate, stimulates digestion, and conserves energy.

8. Explain the mechanism of maintaining resting membrane potential. The resting membrane potential is the negative charge inside a neuron relative to the outside. It is maintained by two key factors:

• Sodium-Potassium Pump: Actively transports 3 Na+ ions out of the cell for every 2 K+ ions it pumps in, creating an electrochemical gradient.
• Differential Permeability: The membrane is more permeable to K+ than to Na+ due to more K+ leak channels, allowing positive charge to leak out of the cell.

9. Describe the process of depolarization in nerve impulse transmission. When a neuron receives a stimulus, voltage-gated sodium (Na+) channels open. Na+ ions rush into the cell, causing the inside of the membrane to become less negative. If this change reaches a certain threshold, it triggers an action potential, or nerve impulse.

10. Explain repolarization and hyperpolarization phases.

• Repolarization: After depolarization, the Na+ channels close and voltage-gated potassium (K+) channels open. K+ ions rush out of the cell, restoring the negative charge inside the membrane.
• Hyperpolarization: The K+ channels close slowly, causing a brief period where the membrane becomes even more negative than its resting state. This is also known as the refractory period, which prevents the impulse from traveling backward.

11. Compare continuous and saltatory conduction.

• Continuous Conduction: Occurs in unmyelinated axons. The action potential moves smoothly and continuously along the entire length of the axon membrane. This process is relatively slow.
• Saltatory Conduction: Occurs in myelinated axons. The impulse "jumps" from one Node of Ranvier to the next, bypassing the myelinated sections. This is much faster and more energy-efficient.

12. Describe the structure and function of a synapse. A synapse is the junction where a nerve impulse is transmitted from one neuron (the presynaptic neuron) to another (the postsynaptic neuron). It includes the axon terminal of the presynaptic neuron, the synaptic cleft (the gap between them), and the dendrite of the postsynaptic neuron. Its function is to ensure that nerve impulses are transmitted in a single direction.

13. Explain synaptic transmission of nerve impulses. When an action potential reaches the axon terminal, it triggers the release of chemical messengers called neurotransmitters into the synaptic cleft. These neurotransmitters travel across the cleft and bind to receptors on the postsynaptic neuron, causing a new electrical signal (either excitatory or inhibitory) in that neuron.

14. List the major parts of forebrain and their functions.

• Cerebrum: The largest part, responsible for intelligence, memory, consciousness, and voluntary actions.
• Thalamus: Acts as a major relay station for sensory information (except smell) going to the cerebrum.
• Hypothalamus: Controls body temperature, hunger, thirst, emotions, and regulates the pituitary gland.

15. Describe the structure and function of midbrain. The midbrain is located between the forebrain and hindbrain. It contains the corpora quadrigemina, which are four swellings involved in processing visual and auditory reflexes. It serves as a crucial connection point between the upper and lower parts of the brain.

16. List the parts of hindbrain and their main functions.

• Pons: Acts as a bridge connecting different brain regions and plays a role in respiration.
• Cerebellum: Coordinates voluntary movements, posture, and balance.
• Medulla Oblongata: Controls vital involuntary functions like heart rate, breathing, and blood pressure.

17. Explain the protective coverings of the brain. The brain is protected by three layers of membranes called meninges:

• Dura Mater: The tough, outermost layer.
• Arachnoid Mater: The web-like middle layer.
• Pia Mater: The delicate innermost layer that clings to the surface of the brain.

18. Describe the formation and circulation of cerebrospinal fluid (CSF). CSF is a clear fluid that surrounds the brain and spinal cord, providing cushioning and protection. It is located within the space between the arachnoid mater and the pia mater. It circulates through the ventricles of the brain and the central canal of the spinal cord, acting as a shock absorber and transporting nutrients and waste.

19. Draw and label a typical reflex arc. A reflex arc is the neural pathway for a reflex action. Its components are:

1. Receptor: Detects the stimulus.
2. Afferent (Sensory) Neuron: Carries the signal to the CNS.
3. Interneuron: Processes the signal within the CNS (spinal cord).
4. Efferent (Motor) Neuron: Carries the response signal from the CNS.
5. Effector: The muscle or gland that carries out the response.

20. Compare monosynaptic and polysynaptic reflexes with examples.

• Monosynaptic Reflex: Involves only one synapse, where a sensory neuron connects directly to a motor neuron. It is very fast. Example: The knee-jerk reflex.
• Polysynaptic Reflex: Involves one or more interneurons between the sensory and motor neurons, meaning there are multiple synapses. This allows for more complex responses. Example: The withdrawal reflex from a hot object.

21. Explain the knee-jerk reflex mechanism. When the patellar tendon below the kneecap is tapped, the quadriceps muscle on the front of the thigh is stretched. Stretch receptors in the muscle are stimulated and send a signal via a sensory neuron to the spinal cord. In the spinal cord, this sensory neuron directly synapses with a motor neuron, which immediately sends a signal back to the quadriceps muscle, causing it to contract and the lower leg to kick forward.

22. Describe the withdrawal reflex pathway. When a hand touches a painful stimulus like a hot object, sensory receptors in the skin are activated. They send an impulse along a sensory neuron to the spinal cord. The sensory neuron synapses with an interneuron, which in turn synapses with a motor neuron. The motor neuron sends an impulse to the flexor muscles of the arm, causing them to contract and pull the hand away from the stimulus.

23. Compare voluntary and involuntary actions.

• Voluntary Actions: Are under conscious control and involve the cerebrum. They are initiated by the individual's will, such as deciding to pick up a book.
• Involuntary Actions: Occur without conscious thought or control. They are regulated by the autonomic nervous system and brainstem. Examples include heartbeat, breathing, and reflex actions.

24. Explain the role of hypothalamus in homeostasis. The hypothalamus is a key control center for maintaining the body's internal balance (homeostasis). It regulates critical functions such as body temperature, hunger and thirst, and sleep-wake cycles. It also links the nervous system to the endocrine system by controlling the pituitary gland, thereby influencing hormone release throughout the body.

25. Describe the function of cerebellum in motor control. The cerebellum is essential for coordinating voluntary movements. It does not initiate movement but refines it, ensuring that actions are smooth, balanced, and precise. It constantly receives sensory information about the body's position and integrates it with motor commands from the cerebrum to maintain posture, balance, and muscle tone.

26. Compare grey matter and white matter in CNS.

• Grey Matter: Consists mainly of neuronal cell bodies, dendrites, unmyelinated axons, and glial cells. It is where synaptic integration and information processing occur. In the brain, it forms the outer cerebral cortex.
• White Matter: Is composed primarily of myelinated axons. The myelin gives it a white appearance. It acts as the communication network, transmitting nerve impulses between different regions of grey matter in the brain and spinal cord.

27. Explain the blood-brain barrier and its significance. The blood-brain barrier is a highly selective semipermeable border that separates the circulating blood from the brain and extracellular fluid in the CNS. It is formed by endothelial cells of the capillaries and astrocytes. Its significance lies in protecting the brain from harmful substances, pathogens, and hormones circulating in the blood while allowing essential nutrients to pass through.

28. Describe the types of glial cells and their functions. Glial cells are non-neuronal cells that support and protect neurons. In the CNS, oligodendrocytes form the myelin sheath. In the PNS, Schwann cells perform the same function. Other glial cells (not detailed in the source text) include astrocytes (which form the blood-brain barrier) and microglia (the immune cells of the CNS).

29. Compare afferent and efferent pathways.

• Afferent (Sensory) Pathways: Consist of sensory neurons that transmit nerve impulses from sensory receptors in the periphery (like skin or organs) towards the central nervous system for processing.
• Efferent (Motor) Pathways: Consist of motor neurons that transmit nerve impulses away from the central nervous system to effector organs, such as muscles or glands, to initiate a response.

30. Explain the all-or-none principle of nerve impulse. The all-or-none principle states that an action potential will either fire at its full, maximum strength or it will not fire at all. There is no such thing as a "strong" or "weak" action potential. As long as the stimulus is strong enough to reach the threshold potential, a complete action potential is generated. If the stimulus is below the threshold, no action potential occurs.

31. Describe the refractory period and its importance. The refractory period is a brief time following an action potential during which a neuron is less responsive to stimulation. It occurs because the voltage-gated sodium channels are inactivated and the potassium channels are open. Its importance is twofold: it ensures that the nerve impulse is a discrete event and, crucially, that it propagates in only one direction down the axon, preventing it from traveling backward.

32. Compare excitatory and inhibitory synapses.

• Excitatory Synapse: At this synapse, the binding of a neurotransmitter to the postsynaptic neuron causes depolarization, making it more likely to fire an action potential.
• Inhibitory Synapse: At this synapse, the binding of a neurotransmitter causes hyperpolarization, making the postsynaptic neuron less likely to fire an action potential.

33. Explain EPSP and IPSP with their significance.

• EPSP (Excitatory Postsynaptic Potential): A temporary depolarization of the postsynaptic membrane caused by an excitatory synapse. Multiple EPSPs can summate to bring the neuron to its firing threshold.
• IPSP (Inhibitory Postsynaptic Potential): A temporary hyperpolarization of the postsynaptic membrane caused by an inhibitory synapse. IPSPs make it harder for a neuron to reach its firing threshold. Their significance lies in synaptic integration, where a neuron sums up all incoming EPSPs and IPSPs to "decide" whether to generate an action potential.

34. Describe the role of calcium ions in synaptic transmission. Calcium ions (Ca2+) are crucial for the release of neurotransmitters. When an action potential arrives at the axon terminal, it causes voltage-gated calcium channels to open. The resulting influx of Ca2+ into the terminal acts as a signal, causing the synaptic vesicles (which contain neurotransmitters) to fuse with the presynaptic membrane and release their contents into the synaptic cleft.

35. Compare cranial and spinal nerves.

• Cranial Nerves: Emerge directly from the brain and brainstem. There are 12 pairs in humans. They primarily serve the head and neck region.
• Spinal Nerves: Emerge from the spinal cord. There are 31 pairs in humans. They serve the rest of the body and are all mixed nerves, meaning they contain both sensory and motor fibers.

36. Explain the organization of autonomic nervous system. The autonomic nervous system (ANS) is a division of the PNS that controls involuntary functions. It is organized into two main branches with opposing actions: the sympathetic division ("fight or flight") and the parasympathetic division ("rest and digest"). It is controlled by centers in the hypothalamus and brainstem and innervates smooth muscle, cardiac muscle, and glands.

37. Describe the fight-or-flight response. The fight-or-flight response is the physiological reaction that occurs in response to a perceived threat, mediated by the sympathetic nervous system. It involves an increase in heart rate, blood pressure, and breathing rate. Blood is diverted to skeletal muscles, pupils dilate, and energy stores are mobilized to prepare the body for intense physical activity.

38. Explain the rest-and-digest response. The rest-and-digest response is mediated by the parasympathetic nervous system. It conserves energy and oversees routine operations. It is characterized by a decrease in heart rate, stimulation of digestive processes (like salivation and peristalsis), and a general state of relaxation.

39. Compare somatic and autonomic nervous systems.

• Somatic Nervous System (SNS): Controls voluntary movements of skeletal muscles. It consists of sensory neurons that carry information from the external environment and motor neurons that lead to conscious actions.
• Autonomic Nervous System (ANS): Controls involuntary functions of internal organs and glands. It operates automatically and is divided into the sympathetic and parasympathetic systems.

40. Describe the structure of spinal cord. The spinal cord is a long, thin, tubular bundle of nervous tissue that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column. It is protected by the vertebrae and meninges. In cross-section, it has a central core of grey matter (shaped like a butterfly) surrounded by outer white matter, which contains the ascending and descending nerve tracts.

41. Explain ascending and descending tracts in spinal cord.

• Ascending Tracts: Are bundles of nerve fibers (white matter) in the spinal cord that carry sensory information from the body up to the brain.
• Descending Tracts: Are bundles of nerve fibers that carry motor commands from the brain down to the appropriate level of the spinal cord to initiate movement.

42. Describe the meningeal layers and their functions. The meninges are three protective membranes covering the CNS:

• Dura Mater: The tough, outermost layer providing durable protection.
• Arachnoid Mater: The web-like middle layer. The subarachnoid space beneath it contains CSF, which acts as a cushion.
• Pia Mater: The delicate inner layer that clings to the brain and spinal cord, supplying blood to the surface.

43. Explain the significance of Nodes of Ranvier. Nodes of Ranvier are the gaps in the myelin sheath of an axon. They are significant because they are the only sites where ion exchange can occur. This forces the action potential to jump from one node to the next (saltatory conduction), which dramatically increases the speed and efficiency of nerve impulse transmission.

44. Compare pseudounipolar and unipolar neurons. Functionally, these terms are often used interchangeably. A unipolar neuron has a single process extending from the cell body which then splits. A pseudounipolar neuron starts as a bipolar neuron during development, but its two processes fuse into a single one. Both types are characteristic of sensory neurons where one branch extends to the periphery and the other to the CNS.

45. Describe the cellular components of nervous tissue. Nervous tissue consists of two main cell types:

• Neurons: The signaling cells that transmit electrical and chemical impulses. They are composed of a cell body, dendrites, and an axon.
• Glial Cells: The non-signaling support cells. They provide structural support, insulation (myelin), nourishment, and immune protection to the neurons.

46. Explain the development of nervous system. The nervous system develops from the ectoderm, the outermost germ layer of the embryo. A specialized region of the ectoderm called the neural plate folds inward to form the neural tube. The anterior part of this tube develops into the brain, and the posterior part develops into the spinal cord.

47. Compare motor and sensory areas of cerebral cortex.

• Sensory Areas: Receive and process sensory information like touch, sight, and sound. The primary somatosensory cortex, for example, creates a map of the body's sensations.
• Motor Areas: Plan and execute voluntary movements. The primary motor cortex directly controls the contraction of skeletal muscles.

48. Describe the limbic system and its functions. The limbic system is a set of brain structures located on both sides of the thalamus. It includes the hippocampus, amygdala, and hypothalamus. It is primarily responsible for processing emotions (like fear and pleasure), forming memories, and regulating motivation.

49. Explain the reticular formation and its role. The reticular formation is a complex network of neurons that runs through the brainstem. It plays a central role in maintaining states of consciousness, arousal, and alertness. It filters incoming sensory stimuli, preventing the brain from being overwhelmed, and also helps regulate sleep-wake cycles.

50. Compare slow and fast nerve fibers.

• Fast Nerve Fibers: Are typically large in diameter and myelinated. They conduct impulses very rapidly (e.g., motor commands to skeletal muscles, sharp pain).
• Slow Nerve Fibers: Are generally smaller in diameter and unmyelinated. They conduct impulses more slowly (e.g., signals for dull, aching pain; many autonomic signals).

51. Describe neuromuscular junction. A neuromuscular junction is a specialized synapse between a motor neuron and a muscle fiber. When a nerve impulse reaches the motor neuron's axon terminal, it releases the neurotransmitter acetylcholine. Acetylcholine binds to receptors on the muscle fiber, causing it to depolarize and contract.

52. Explain the mechanism of muscle contraction control. The brain initiates a voluntary movement in the motor cortex. This signal travels down the spinal cord and along a motor neuron to the neuromuscular junction. The release of acetylcholine triggers an action potential in the muscle fiber, which leads to the release of calcium from internal stores, causing the muscle filaments (actin and myosin) to slide past each other and the muscle to contract.

53. Compare skeletal, smooth, and cardiac muscle innervation.

• Skeletal Muscle: Innervated by the somatic nervous system (voluntary control).
• Smooth Muscle: Innervated by the autonomic nervous system (involuntary control).
• Cardiac Muscle: Innervated by the autonomic nervous system (involuntary control), which modifies its intrinsic rhythm.

54. Describe pain pathways in nervous system. Pain signals (nociception) are detected by specialized sensory receptors. The signal travels along sensory neurons to the spinal cord, where it synapses with other neurons. These neurons then carry the pain signal up ascending tracts to the thalamus in the brain, which relays the information to the cerebral cortex for conscious perception of pain.

55. Explain referred pain mechanism. Referred pain is the perception of pain in a location other than the site of the painful stimulus. It occurs because sensory nerves from different parts of the body share common nerve pathways in the spinal cord. The brain misinterprets the origin of the signal, for example, pain from the heart (angina) may be felt in the left arm.

56. Compare acute and chronic pain.

• Acute Pain: Is a direct response to tissue damage and is short-lived. It serves as a warning signal and resolves when the underlying cause is treated.
• Chronic Pain: Is pain that persists for weeks, months, or years, often outlasting the initial injury. It can be considered a disease state in itself and may not have a clear cause.

57. Describe the gate control theory of pain. This theory suggests that the spinal cord contains a neurological "gate" that can block or allow pain signals to pass to the brain. Non-painful input (like rubbing an injured area) can close the gate by activating other nerve fibers, which inhibits the transmission of pain signals from pain neurons, thus reducing the perception of pain.

58. Explain endogenous pain control mechanisms. The brain has its own pain-suppressing (analgesic) system. In response to stimuli like stress or exercise, the brain can release endogenous opioids, such as endorphins. These substances bind to opioid receptors in the brain and spinal cord, blocking the transmission of pain signals.

59. Compare sensory and motor homunculus.

• Sensory Homunculus: A distorted representation of the human body, mapped onto the somatosensory cortex. The size of each body part is proportional to the amount of sensory input it provides (e.g., large lips and hands).
• Motor Homunculus: A similar map on the primary motor cortex. The size of each body part is proportional to the complexity of motor control required (e.g., large hands and face for fine movements).

60. Describe brain waves and their significance. Brain waves are the rhythmic electrical patterns generated by the synchronized activity of neurons in the brain, measured by an EEG. Different patterns (beta, alpha, theta, delta) correspond to different states of consciousness, such as alertness, relaxation, light sleep, and deep sleep. Their analysis can help diagnose conditions like epilepsy and sleep disorders.

61. Explain sleep-wake cycle regulation. The sleep-wake cycle is primarily regulated by the hypothalamus, which contains the body's master biological clock (the suprachiasmatic nucleus). This clock responds to light cues from the eyes and coordinates the release of hormones like melatonin (which promotes sleep) and cortisol (which promotes wakefulness) to maintain a roughly 24-hour circadian rhythm.

62. Compare REM and NREM sleep.

• NREM (Non-Rapid Eye Movement) Sleep: Consists of several stages of progressively deeper sleep. It is characterized by slow brain waves, reduced muscle activity, and is thought to be important for physical restoration.
• REM (Rapid Eye Movement) Sleep: A stage of sleep characterized by rapid eye movements, active brain waves similar to wakefulness, and muscle paralysis. This is when most vivid dreaming occurs and is thought to be crucial for memory consolidation.

63. Describe circadian rhythm control. Circadian rhythms are the body's natural 24-hour cycles of physical, mental, and behavioral changes. They are controlled by a master clock in the hypothalamus (the SCN), which is synchronized primarily by light exposure. This clock regulates the timing of sleep, hormone release, body temperature, and other important functions.

64. Explain memory formation and types. Memory formation involves encoding (processing new information), storage (maintaining information over time), and retrieval (accessing stored information). The main types are:

• Short-Term Memory: Holds a small amount of information for a brief period.
• Long-Term Memory: The vast, relatively permanent storage of information.

65. Compare short-term and long-term memory.

• Short-Term Memory: Has a limited capacity (about 7 items) and a short duration (seconds to minutes) unless rehearsed. It is fragile and easily disrupted.
• Long-Term Memory: Has a virtually unlimited capacity and can last a lifetime. It is more stable and is formed through processes of consolidation, often involving structural changes in the brain.

66. Describe learning mechanisms in brain. Learning involves changes in the strength of synaptic connections between neurons. When two neurons are frequently activated together, the connection between them strengthens (a process called long-term potentiation, or LTP). This makes it more likely that activating one neuron will activate the other in the future, forming the neural basis of a learned association.

67. Explain habituation and sensitization. These are two simple forms of non-associative learning:

• Habituation: A decrease in response to a repeated, harmless stimulus. It is learning to ignore something that is irrelevant (e.g., tuning out a constant background noise).
• Sensitization: An increased response to a wide range of stimuli after exposure to a particularly strong or noxious one. It is a state of heightened arousal.

68. Compare classical and operant conditioning.

• Classical Conditioning: Involves forming an association between two stimuli. A neutral stimulus becomes associated with a stimulus that naturally produces a behavior, so that over time the neutral stimulus alone elicits the behavior (e.g., Pavlov's dogs salivating at the sound of a bell).
• Operant Conditioning: Involves forming an association between a behavior and a consequence (reinforcement or punishment). The likelihood of a behavior being repeated is increased by reinforcement and decreased by punishment.

69. Describe language areas in brain. For most right-handed individuals, language is processed in the left hemisphere:

• Broca's Area: Located in the frontal lobe, it is responsible for speech production and articulation.
• Wernicke's Area: Located in the temporal lobe, it is responsible for language comprehension and understanding.

70. Explain lateralization of brain functions. Brain lateralization is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain. For example, for most people, the left hemisphere is dominant for language and logical processing, while the right hemisphere is dominant for spatial awareness, facial recognition, and emotional processing.

71. Compare Broca's and Wernicke's areas.

• Broca's Area: Is a motor speech area. Damage to it (Broca's aphasia) results in difficulty producing fluent, grammatical speech, although comprehension remains relatively intact.
• Wernicke's Area: Is a sensory speech area. Damage to it (Wernicke's aphasia) results in difficulty understanding language; the person can produce fluent but meaningless speech.

72. Describe motor learning and skill acquisition. Motor learning is the process of improving the smoothness and accuracy of movements through practice. It involves the cerebellum, basal ganglia, and motor cortex. Initially, movements are conscious and clumsy, but with repetition, they become automatic and are stored as a motor program, allowing for fast and effortless execution.

73. Explain plasticity in developing nervous system. Neuroplasticity is the brain's ability to reorganize itself by forming new neural connections. This ability is highest during development, allowing a child's brain to be shaped by experience, learning, and sensory input. It is the mechanism by which the brain adapts and learns.

74. Compare regeneration in CNS and PNS.

• PNS: Axons in the peripheral nervous system have a limited but significant ability to regenerate after injury, guided by the remaining Schwann cell sheath.
• CNS: Axon regeneration in the central nervous system is severely limited. This is due to the formation of scar tissue by glial cells and the presence of inhibitory molecules that actively block regrowth.

75. Describe common neurodegenerative diseases. Neurodegenerative diseases are characterized by the progressive loss of structure or function of neurons. Common examples include:

• Alzheimer's Disease: Affects memory and cognition.
• Parkinson's Disease: Affects motor control.
• Multiple Sclerosis: Affects the myelin sheath, disrupting nerve communication.

76. Explain multiple sclerosis pathophysiology. Multiple sclerosis (MS) is an autoimmune disease where the body's own immune system attacks and destroys the myelin sheath that insulates axons in the CNS. This demyelination disrupts the flow of nerve impulses, leading to a wide range of sensory, motor, and cognitive symptoms.

77. Compare Parkinson's and Alzheimer's diseases.

• Parkinson's Disease: Is primarily a motor disorder caused by the death of dopamine-producing neurons in the substantia nigra (part of the basal ganglia). Symptoms include tremor, rigidity, and slowness of movement.
• Alzheimer's Disease: Is primarily a cognitive disorder characterized by the formation of amyloid plaques and tau tangles in the brain, leading to widespread neuronal death, especially in the hippocampus and cerebral cortex. This causes memory loss and dementia.

78. Describe epilepsy and its types. Epilepsy is a neurological disorder characterized by recurrent, unprovoked seizures, which are sudden surges of abnormal electrical activity in the brain. Seizures can be:

• Focal (Partial): Originating in one area of the brain.
• Generalized: Affecting both sides of the brain from the start.

79. Explain stroke types and consequences.

• Ischemic Stroke: The most common type, caused by a blood clot blocking an artery to the brain.
• Hemorrhagic Stroke: Caused by a blood vessel rupturing and bleeding into the brain. Consequences depend on the location and extent of brain damage but can include paralysis, speech problems, memory loss, and death.

80. Compare spinal cord injuries and their effects. Spinal cord injuries are classified by the level (e.g., cervical, thoracic) and completeness of the injury.

• Complete Injury: Results in a total loss of sensory and motor function below the level of the injury.
• Incomplete Injury: Some function remains below the level of the injury. Higher injuries (e.g., cervical) result in more widespread paralysis (quadriplegia) than lower injuries (paraplegia).

81. Describe traumatic brain injury classifications. Traumatic brain injury (TBI) is typically classified by severity:

• Mild (e.g., concussion): Brief or no loss of consciousness.
• Moderate: Loss of consciousness for minutes to hours, with some confusion.
• Severe: Prolonged period of unconsciousness or coma. Classification helps predict prognosis and guide treatment.

82. Explain concussion and its effects. A concussion is a mild traumatic brain injury caused by a jolt or blow to the head, causing the brain to move rapidly inside the skull. Effects can include headache, confusion, dizziness, memory problems, and mood changes. While usually temporary, repeated concussions can have long-term consequences.

83. Compare sensory and motor deficits.

• Sensory Deficits: Involve the loss or impairment of sensation, such as numbness, tingling, or blindness. They result from damage to sensory receptors or afferent pathways.
• Motor Deficits: Involve the loss or impairment of movement, such as weakness or paralysis. They result from damage to motor areas of the brain or efferent pathways.

84. Describe rehabilitation principles in neurological disorders. Neurological rehabilitation aims to maximize a patient's functional independence. Key principles include:

• Neuroplasticity: Using repetitive, task-specific training to encourage the brain to rewire itself.
• Compensation: Teaching patients new ways to perform tasks to work around their deficits.
• Early Intervention: Starting rehabilitation as soon as medically stable to achieve the best outcomes.

85. Explain neuroimaging techniques. Neuroimaging techniques allow for the visualization of the brain's structure or function.

• Structural Imaging (e.g., CT, MRI): Shows the anatomy of the brain, useful for identifying tumors, strokes, or injuries.
• Functional Imaging (e.g., fMRI, PET): Shows brain activity by measuring blood flow or metabolism, useful for research and diagnosing metabolic diseases.

86. Compare CT and MRI in brain imaging.

• CT (Computed Tomography) Scan: Uses X-rays to create cross-sectional images. It is fast and good for detecting acute bleeding (hemorrhagic stroke) and bone fractures.
• MRI (Magnetic Resonance Imaging): Uses magnetic fields and radio waves. It provides much more detailed images of soft tissues, making it superior for detecting tumors, ischemic strokes, and subtle structural changes.

87. Describe EEG and its applications. An electroencephalogram (EEG) records the electrical activity of the brain via electrodes placed on the scalp. It measures brain waves. Its main applications are in the diagnosis of epilepsy, evaluation of sleep disorders, and monitoring brain activity during surgery or in a coma.

88. Explain nerve conduction studies. A nerve conduction study (NCS) measures how fast an electrical impulse moves through a nerve. It can help detect nerve damage or disease by showing if a nerve is conducting signals too slowly. It is often used to diagnose conditions like carpal tunnel syndrome or peripheral neuropathy.

89. Compare local and general anesthetics.

• Local Anesthetics: Block nerve conduction in a specific, targeted area of the body, causing a loss of sensation without loss of consciousness.
• General Anesthetics: Act on the central nervous system to induce a reversible state of unconsciousness, providing amnesia, analgesia, and muscle relaxation for major surgery.

90. Describe analgesic mechanisms. Analgesics are pain-relieving drugs. Their mechanisms vary:

• Opioids (e.g., morphine): Mimic endogenous endorphins, binding to opioid receptors in the CNS to block pain signals.
• NSAIDs (e.g., ibuprofen): Reduce pain and inflammation at the site of injury by blocking the production of prostaglandins.

91. Explain neurotoxins and their effects. Neurotoxins are substances that are poisonous or destructive to nervous tissue. They can act in various ways, such as blocking ion channels (e.g., tetrodotoxin from pufferfish causes paralysis) or interfering with neurotransmitter release (e.g., botulinum toxin causes paralysis by blocking acetylcholine release).

92. Compare stimulants and depressants.

• Stimulants (e.g., caffeine, amphetamines): Increase CNS activity, leading to heightened alertness, attention, and energy.
• Depressants (e.g., alcohol, benzodiazepines): Decrease CNS activity, leading to relaxation, sedation, and reduced anxiety.

93. Describe addiction mechanisms in brain. Addiction involves the brain's reward pathway, particularly the release of the neurotransmitter dopamine in the nucleus accumbens. Addictive drugs hijack this system, causing a large and rapid release of dopamine, which reinforces the drug-taking behavior. Over time, this leads to long-term changes in brain structure and function that underlie compulsive drug use.

94. Explain tolerance and withdrawal.

• Tolerance: The diminishing effect of a drug after repeated administration, requiring the user to take larger doses to achieve the same effect. It occurs as the brain adapts to the drug's presence.
• Withdrawal: The unpleasant physical and psychological symptoms that occur when a person stops taking a drug they are dependent on. These symptoms are often the opposite of the drug's effects.

95. Compare neurological and psychiatric disorders.

• Neurological Disorders: Are diseases of the central and peripheral nervous system with a clear structural or biochemical cause (e.g., stroke, Parkinson's disease, epilepsy).
• Psychiatric Disorders: Are primarily disorders of mood, thought, or behavior. While they have a neurobiological basis, they are diagnosed based on behavioral and psychological criteria (e.g., depression, schizophrenia).

96. Describe stress response pathways. The two main pathways are:

• Sympathetic-Adrenal-Medullary (SAM) System: The fast, immediate response. The sympathetic nervous system stimulates the adrenal medulla to release adrenaline, causing the "fight or flight" response.
• Hypothalamic-Pituitary-Adrenal (HPA) Axis: The slower, more sustained response. The hypothalamus stimulates the pituitary, which tells the adrenal cortex to release cortisol, a stress hormone that mobilizes energy.

97. Explain psychosomatic disorders. Psychosomatic disorders are conditions where psychological stress and emotional factors contribute to or worsen physical symptoms. The mental state directly affects physical health. For example, chronic stress can contribute to high blood pressure, tension headaches, or stomach ulcers.

98. Compare acute and chronic stress effects.

• Acute Stress: The short-term stress response ("fight or flight") is adaptive and can enhance performance and survival.
• Chronic Stress: Prolonged activation of the stress response is harmful. It can lead to a weakened immune system, high blood pressure, anxiety, depression, and an increased risk for many diseases.

99. Describe meditation effects on brain. Regular meditation has been shown to cause structural and functional changes in the brain. These include increased grey matter density in areas associated with attention, emotional regulation, and self-awareness (like the prefrontal cortex and insula), and decreased activity in the amygdala (the brain's fear center).

100. Explain exercise benefits for nervous system. Physical exercise benefits the nervous system by increasing blood flow to the brain, promoting the growth of new neurons (neurogenesis), and increasing the levels of neurotransmitters like dopamine and serotonin. This can improve mood, enhance cognitive function, reduce the risk of neurodegenerative diseases, and alleviate symptoms of depression.

Answers for Section D: Long Answer Questions (3 marks each)

Here are the answers to the questions in Section D, based on the provided document "5.5_Neural_Control_and_Coordination.md".

1. Draw a detailed diagram of a neuron and explain the function of each part in nerve impulse transmission. A neuron is the fundamental unit of the nervous system, specialized for transmitting information.

• Cell Body (Soma): This is the neuron's core, containing the nucleus and essential organelles. It maintains the neuron's health and metabolic functions.
• Dendrites: These are tree-like extensions that serve as the primary receivers of signals from other neurons. They collect incoming nerve impulses and transmit them toward the cell body.
• Axon: This is a single, long fiber that carries nerve impulses away from the cell body. It originates from the axon hillock. Many axons are covered by a myelin sheath, an insulating layer that dramatically speeds up impulse transmission. The impulse jumps between gaps in the sheath called Nodes of Ranvier. The axon ends in axon terminals, which release neurotransmitters to communicate with the next cell.

2. Describe the classification of neurons based on structure and function with suitable examples. Neurons can be classified in two main ways:

• Based on Structure:
  • Multipolar: Have one axon and many dendrites. They are the most common type. Example: Neurons in the cerebral cortex.
  • Bipolar: Have one axon and one dendrite extending from opposite ends of the cell body. Example: Neurons in the retina of the eye.
  • Unipolar: Have a single process that leaves the cell body and then divides into two branches (one acting as a dendrite, the other as an axon). Example: Sensory neurons in the dorsal root ganglia of the spinal cord.
• Based on Function:
  • Sensory (Afferent): Carry signals from sensory receptors towards the CNS. Example: A neuron carrying a pain signal from the skin.
  • Motor (Efferent): Carry signals from the CNS to muscles and glands (effectors). Example: A neuron causing a muscle to contract.
  • Interneurons: Found exclusively in the CNS, they connect and integrate signals between sensory and motor neurons.

3. Explain the detailed mechanism of nerve impulse conduction along a myelinated axon. Nerve impulse conduction in a myelinated axon, known as saltatory conduction, is a rapid and efficient process.

1. Resting State: The axon maintains a resting potential, with the inside being negative relative to the outside, thanks to the sodium-potassium pump.
2. Initiation: An action potential is generated at the axon hillock.
3. Jumping Impulse: The myelin sheath acts as an insulator, preventing ion flow across the membrane. The action potential does not travel along the myelinated parts but instead "jumps" from one Node of Ranvier (a gap in the myelin) to the next.
4. Node Depolarization: At each node, the influx of Na+ ions is strong enough to depolarize the next node to its threshold, triggering a new action potential there.
5. Unidirectional Flow: This process repeats down the axon. The refractory period following an action potential at each node ensures the impulse can only travel in one direction, away from the cell body. This method is significantly faster than continuous conduction in unmyelinated axons.

4. Compare and contrast the organization and functions of central and peripheral nervous systems.

• Central Nervous System (CNS):
  • Organization: Composed of the brain and spinal cord. It is encased in bone (skull and vertebral column) and protected by the meninges and cerebrospinal fluid.
  • Function: It is the body's main information processing and integration center. It receives sensory information, interprets it, and initiates motor responses. All learning, memory, and emotion are processed here.
• Peripheral Nervous System (PNS):
  • Organization: Consists of all nervous tissue outside the CNS, primarily cranial and spinal nerves that branch out to all parts of the body.
  • Function: It acts as the communication link between the CNS and the rest of the body. It carries sensory information to the CNS and motor commands from the CNS to muscles and glands. It is further divided into the somatic (voluntary) and autonomic (involuntary) systems.

5. Describe the autonomic nervous system with its subdivisions and their contrasting effects on body organs. The Autonomic Nervous System (ANS) regulates involuntary bodily functions. It has two main subdivisions with opposing actions:

• Sympathetic Nervous System: This division prepares the body for "fight or flight" situations that require immediate action.
  • Effects: Increases heart rate and blood pressure, dilates pupils, slows digestion, and mobilizes energy stores. It readies the body for peak physical exertion.
• Parasympathetic Nervous System: This division controls "rest and digest" functions, conserving energy.
  • Effects: Decreases heart rate, stimulates digestion and other metabolic processes, and constricts pupils. It is active when the body is at rest. Together, these two systems maintain homeostasis by balancing each other's effects.

6. Explain the ionic basis of resting membrane potential and action potential generation.

• Resting Membrane Potential: In a resting neuron, the inside is about -70mV relative to the outside. This is established by:
  1. The sodium-potassium pump, which actively pumps 3 Na+ ions out for every 2 K+ ions in.
  2. The membrane's higher permeability to K+ ions, allowing them to leak out and make the inside more negative.
• Action Potential Generation: This is the nerve impulse, an "all-or-none" event.
  1. Stimulus & Depolarization: A stimulus causes voltage-gated Na+ channels to open. Na+ rushes in, making the inside of the membrane positive.
  2. Repolarization: The Na+ channels close, and voltage-gated K+ channels open. K+ rushes out, restoring the negative charge inside.
  3. Hyperpolarization: K+ channels close slowly, causing a brief "undershoot" where the membrane is more negative than at rest. This refractory period ensures the impulse moves in one direction.

7. Describe synaptic transmission including the role of neurotransmitters and synaptic integration. Synaptic transmission is the process of sending a signal from one neuron to another across a synapse.

1. Arrival of Action Potential: When an impulse reaches the axon terminal of the presynaptic neuron, it triggers the opening of voltage-gated calcium channels.
2. Neurotransmitter Release: The influx of calcium causes synaptic vesicles, which are small sacs containing neurotransmitters, to fuse with the presynaptic membrane and release their contents into the synaptic cleft.
3. Binding to Receptors: Neurotransmitters diffuse across the cleft and bind to specific receptors on the postsynaptic neuron's membrane.
4. Postsynaptic Potential: This binding opens ion channels on the postsynaptic neuron, causing either an excitatory (depolarizing) or inhibitory (hyperpolarizing) potential. A single neuron receives thousands of these inputs, and it integrates them to determine whether it will fire an action potential of its own.

8. Draw a detailed diagram of human brain and explain the functions of its major parts. The human brain is divided into three main regions:

• Forebrain:
  • Cerebrum: The largest part, responsible for higher-order functions like thought, language, memory, and voluntary movement. Its outer layer is the cerebral cortex.
  • Thalamus: The main relay center for sensory signals on their way to the cerebral cortex.
  • Hypothalamus: A vital control center for homeostasis, regulating body temperature, hunger, thirst, and the endocrine system via the pituitary gland.
• Midbrain: Connects the forebrain and hindbrain. It contains centers for visual and auditory reflexes (corpora quadrigemina).
• Hindbrain:
  • Pons: Connects the cerebellum and cerebrum; involved in controlling respiration.
  • Cerebellum: Crucial for coordinating movement, posture, and balance.
  • Medulla Oblongata: Controls the most basic, vital involuntary functions, including heart rate, breathing, and blood pressure.

9. Explain the concept of reflex action with detailed description of monosynaptic and polysynaptic reflexes. A reflex action is a rapid, involuntary response to a stimulus, mediated by a neural pathway called a reflex arc.

• Reflex Arc Components: Receptor, sensory neuron, integration center (spinal cord), motor neuron, and effector.
• Monosynaptic Reflex: This is the simplest and fastest type of reflex, involving only one synapse. The sensory neuron synapses directly with the motor neuron in the spinal cord.
  • Example: Knee-jerk Reflex. Tapping the patellar tendon stretches the quadriceps muscle. The sensory neuron from the muscle sends a signal to the spinal cord and directly activates the motor neuron to the quadriceps, causing it to contract and the leg to kick.
• Polysynaptic Reflex: This reflex involves one or more interneurons, meaning there are at least two synapses. This allows for more complex responses and integration.
  • Example: Withdrawal Reflex. Touching a hot object stimulates a pain receptor. The sensory neuron carries the signal to the spinal cord, where it synapses with an interneuron. The interneuron then activates a motor neuron, causing muscles to contract and pull the hand away.

10. Describe the protective mechanisms of the central nervous system including meninges and CSF. The CNS (brain and spinal cord) is highly protected by several layers.

1. Bone: The brain is encased in the skull, and the spinal cord is protected by the vertebral column.
2. Meninges: These are three protective membranes that lie between the bone and the nervous tissue:
   • Dura Mater: The tough, fibrous outermost layer.
   • Arachnoid Mater: A web-like middle layer.
   • Pia Mater: A delicate inner layer that adheres directly to the surface of the brain and spinal cord.
3. Cerebrospinal Fluid (CSF): This clear fluid circulates in the space between the arachnoid and pia mater (the subarachnoid space) and within the ventricles of the brain. It acts as a liquid cushion, absorbing shock and protecting the CNS from trauma. It also helps in the exchange of nutrients and waste products between the blood and the brain.

11. Describe the cellular organization of nervous tissue including neurons and glial cells. Nervous tissue is composed of two main types of cells: neurons and glial cells.

• Neurons: Are the primary signaling cells. They are structurally and functionally specialized to transmit electrical and chemical signals. Each neuron typically has a cell body, dendrites to receive signals, and an axon to send signals.
• Glial Cells: Are the support cells of the nervous system. They do not transmit nerve impulses but are essential for neuronal function and survival. In the PNS, Schwann cells form the myelin sheath. In the CNS, oligodendrocytes form the myelin sheath. Other types (not detailed in the source text) provide structural support, nourishment, and immune defense.

12. Explain the functional organization of cerebral cortex with motor and sensory areas. The cerebral cortex is the outer layer of the cerebrum and is the site of conscious thought and processing. It is broadly organized into functional areas:

• Sensory Areas: Receive and process sensory information from the body. For example, the primary somatosensory cortex receives information about touch, temperature, and pain from the skin.
• Motor Areas: Control voluntary movements. The primary motor cortex initiates commands to move skeletal muscles.
• Association Areas: These areas make up the majority of the cortex and are involved in higher mental functions. They integrate information from sensory and motor areas and are responsible for functions like language, memory, and decision-making.

13. Describe the role of hypothalamus in maintaining homeostasis and endocrine regulation. The hypothalamus is a small but critical brain region that serves as the primary link between the nervous system and the endocrine system. It maintains homeostasis by regulating body temperature, hunger, thirst, fatigue, and circadian rhythms. For endocrine regulation, it controls the pituitary gland, often called the "master gland." By secreting releasing and inhibiting hormones, the hypothalamus directs the pituitary to release its own hormones, which in turn control many other endocrine glands and bodily functions.

14. Explain the structure and function of cerebellum in motor control and balance. The cerebellum, located at the back of the brain, consists of two hemispheres and a convoluted surface. Its primary function is the coordination of voluntary motor activity. It doesn't initiate movement but acts as a modulator, receiving input from sensory systems and from other parts of the brain and integrating these inputs to fine-tune motor activity. This results in smooth, balanced muscular movements and is essential for maintaining posture, balance, and muscle tone.

15. Describe the brain stem and its vital functions in maintaining life processes. The brain stem is the posterior part of the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, pons, and medulla oblongata. It is responsible for many vital, involuntary functions essential for life. The medulla oblongata controls heart rate, blood pressure, and breathing. The pons is involved in respiration and serves as a relay station. The midbrain contains centers for auditory and visual reflexes. The brain stem as a whole also regulates consciousness, sleep, and alertness.

16. Explain the mechanism of pain perception and modulation in the nervous system. Pain perception begins when nociceptors (pain receptors) are activated by a noxious stimulus. The signal travels along fast A-delta fibers (for sharp pain) or slow C fibers (for dull pain) to the spinal cord. There, the signal is relayed up to the thalamus and then to the somatosensory cortex for conscious perception. The nervous system can modulate pain through the gate control theory and via descending pathways from the brainstem that release endogenous opioids (like endorphins) to inhibit the ascending pain signals.

17. Describe the neural basis of memory formation, storage, and retrieval. Memory formation (encoding) involves sensory processing followed by consolidation, a process that stabilizes a memory trace. The hippocampus is critical for consolidating short-term memories into long-term memories. Long-term storage is believed to involve widespread, lasting structural changes in the cerebral cortex, a process called long-term potentiation (LTP), which strengthens synaptic connections. Retrieval is the process of accessing these stored memories, often triggered by cues, and is thought to involve the prefrontal cortex.

18. Explain the sleep-wake cycle regulation and the role of circadian rhythms. The sleep-wake cycle is a primary circadian rhythm, an approximately 24-hour cycle driven by an internal biological clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN receives light cues from the retina to synchronize with the day-night cycle. It promotes wakefulness by stimulating arousal centers in the brainstem and promotes sleep by signaling the pineal gland to release melatonin as light levels decrease.

19. Describe the neural control of voluntary and involuntary movements.

• Voluntary Movements: Are initiated in the primary motor cortex of the cerebrum. The plan for movement is refined by the basal ganglia and cerebellum. The command travels down descending motor pathways (corticospinal tracts) through the spinal cord to motor neurons, which activate skeletal muscles.
• Involuntary Movements: Are controlled by lower brain centers and the autonomic nervous system. The brainstem (medulla, pons) controls vital functions like breathing and heart rate. The hypothalamus directs the ANS, which controls smooth muscle, cardiac muscle, and glands without conscious input.

20. Explain the sensory pathways from receptors to cerebral cortex. A sensory pathway begins with a sensory receptor detecting a specific stimulus (e.g., touch, light). The receptor transduces this into an electrical signal, which travels along a first-order sensory neuron to the spinal cord or brainstem. It synapses with a second-order neuron, which crosses to the opposite side and ascends to the thalamus. In the thalamus, it synapses with a third-order neuron that projects to the appropriate area of the somatosensory cortex for conscious perception.

21. Describe the motor pathways from cerebral cortex to muscles. Voluntary motor commands originate in the primary motor cortex. The signal travels along an upper motor neuron down through the brain and brainstem. Most of these pathways (corticospinal tracts) cross to the opposite side in the medulla. The upper motor neuron then synapses in the spinal cord with a lower motor neuron. The axon of this lower motor neuron exits the spinal cord and travels to a skeletal muscle, where it forms a neuromuscular junction and stimulates contraction.

22. Explain the integration of sensory and motor functions in spinal cord. The spinal cord is more than just a relay station; it is a key site of integration. It contains the circuitry for reflexes, allowing for rapid motor responses to sensory input without involving the brain (e.g., withdrawal reflex). It also contains central pattern generators, which are neural circuits that can produce rhythmic motor outputs, such as those needed for walking, based on simple commands from the brain.

23. Describe the cranial nerves with their origins, courses, and functions. There are 12 pairs of cranial nerves that originate from the brain and brainstem. They provide sensory and motor functions mainly to the head and neck. Key examples include:

• I. Olfactory: Sensory for smell.
• II. Optic: Sensory for vision.
• V. Trigeminal: Sensory for the face and motor for chewing.
• VII. Facial: Motor for facial expression and sensory for taste.
• X. Vagus: A major autonomic nerve that innervates many thoracic and abdominal organs.

24. Explain the formation, circulation, and functions of cerebrospinal fluid. Formation: CSF is produced from blood plasma by specialized tissue called the choroid plexus, located within the brain's ventricles. Circulation: It flows from the lateral ventricles to the third and fourth ventricles, then into the subarachnoid space surrounding the brain and spinal cord. It is eventually reabsorbed back into the blood. Functions: Its primary roles are to provide mechanical protection (cushioning), maintain chemical stability for the brain, and assist in nutrient supply and waste removal.

25. Describe the blood-brain barrier, its structure, and physiological significance. Structure: The blood-brain barrier is a highly selective barrier formed by the endothelial cells of brain capillaries, which are joined by tight junctions, and supported by astrocytes. Physiological Significance: It strictly regulates the passage of substances from the bloodstream into the brain's extracellular fluid. This protects the brain from circulating toxins, pathogens, and fluctuations in hormones and ions that could disrupt neural function, while actively transporting essential molecules like glucose and amino acids.

26. Explain the process of myelination and its importance in nerve conduction. Myelination is the process where glial cells (Oligodendrocytes in the CNS, Schwann cells in the PNS) wrap their membranes around an axon to form a fatty, insulating layer called the myelin sheath. This sheath is not continuous but has gaps called Nodes of Ranvier. Its importance is that it forces the nerve impulse to jump from node to node (saltatory conduction), which is dramatically faster and more energy-efficient than the continuous conduction seen in unmyelinated axons.

27. Describe the neuromuscular junction and mechanism of muscle contraction control. The neuromuscular junction is the chemical synapse where a motor neuron transmits a signal to a muscle fiber. When an action potential arrives, the neuron releases acetylcholine (ACh). ACh binds to receptors on the muscle fiber's membrane, opening ion channels and causing a depolarization that triggers an action potential in the muscle. This muscle action potential propagates along the fiber and leads to the release of internal calcium, initiating the sliding of myofilaments and thus, muscle contraction.

28. Explain the neural control of breathing and cardiovascular functions. These vital functions are primarily controlled by autonomic centers in the brainstem, specifically the medulla oblongata and pons.

• Breathing: The respiratory center in the medulla sets the basic rhythm of breathing by controlling the diaphragm and intercostal muscles. It receives input regarding blood oxygen and CO2 levels to adjust the rate and depth.
• Cardiovascular: The cardiovascular center in the medulla regulates heart rate and blood pressure by sending signals to the heart and blood vessels via the sympathetic and parasympathetic nerves.

29. Describe the limbic system and its role in emotions and behavior. The limbic system is a group of interconnected brain structures, including the amygdala, hippocampus, and hypothalamus, that is central to emotion, memory, and motivation. The amygdala is key for processing fear and emotional responses. The hippocampus is crucial for forming new memories. The limbic system as a whole integrates emotional states with stored memories, influencing behavior and decision-making.

30. Explain the reticular formation and its functions in consciousness and arousal. The reticular formation is a diffuse network of neurons extending throughout the brainstem. It has a critical role in regulating arousal and consciousness. Its ascending projections, known as the reticular activating system (RAS), send a continuous stream of impulses to the cerebral cortex, keeping it alert and conscious. It also filters incoming sensory information, allowing only relevant stimuli to reach our conscious awareness.

31. Describe the visual pathway from eye to visual cortex. Light enters the eye and is focused on the retina, activating photoreceptor cells (rods and cones). The signal is processed by bipolar and ganglion cells. The axons of the ganglion cells form the optic nerve. The two optic nerves meet at the optic chiasm, where fibers from the nasal half of each retina cross over. The signals then travel via the optic tracts to the thalamus, which relays them to the primary visual cortex in the occipital lobe for conscious perception of sight.

32. Explain the auditory pathway from ear to auditory cortex. Sound waves are converted into mechanical vibrations by the eardrum and middle ear bones, and then into fluid waves in the cochlea of the inner ear. These waves stimulate hair cells, which generate nerve impulses. The impulses travel along the auditory nerve to the brainstem, then to the thalamus, and finally to the primary auditory cortex in the temporal lobe, where they are interpreted as sound.

33. Describe the gustatory and olfactory pathways.

• Gustatory (Taste): Taste receptors on the tongue detect chemicals in food and send signals through cranial nerves (Facial, Glossopharyngeal) to the brainstem. From there, the signals are relayed to the thalamus and then to the gustatory cortex for the conscious perception of taste.
• Olfactory (Smell): Olfactory receptors in the nasal cavity detect airborne chemicals. Their axons form the olfactory nerve, which projects directly to the olfactory bulb in the brain, bypassing the thalamus. From the olfactory bulb, signals are sent to the olfactory cortex and parts of the limbic system, which is why smells are often strongly linked to memory and emotion.

34. Explain the somatosensory pathways for touch, temperature, and pain. Sensory receptors in the skin and body detect stimuli like touch, pressure, temperature, and pain. The signals travel along sensory neurons to the spinal cord. In the spinal cord, they synapse and ascend to the thalamus via different tracts (e.g., the spinothalamic tract for pain and temperature). The thalamus then relays the information to the primary somatosensory cortex, where the sensation is consciously perceived and localized.

35. Describe the proprioceptive pathways and their role in body awareness. Proprioceptors are sensory receptors located in muscles, tendons, and joints that provide information about the position and movement of body parts. This information travels up the spinal cord in specific tracts (like the dorsal columns) to the cerebellum and the somatosensory cortex. This allows the brain to have a constant, unconscious awareness of the body's position in space, which is crucial for coordinating movement and balance.

36. Explain the vestibular system and its role in balance and spatial orientation. The vestibular system, located in the inner ear, is responsible for the sense of balance and spatial orientation. It consists of semicircular canals that detect rotational movements of the head, and otolith organs that detect linear acceleration and gravity. Information from this system is sent to the brainstem and cerebellum to help maintain balance, stabilize the head and body during movement, and maintain posture.

37. Describe the neural control of digestive system functions. The digestive system is regulated by the autonomic nervous system and its own intrinsic nervous system (the enteric nervous system).

• Parasympathetic Nervous System: Stimulates digestion ("rest and digest") by increasing peristalsis, secretions, and blood flow to the gut.
• Sympathetic Nervous System: Inhibits digestion ("fight or flight") by decreasing peristalsis and blood flow.

38. Explain the neural regulation of body temperature. The hypothalamus acts as the body's thermostat. It contains temperature-sensitive neurons that monitor blood temperature. If the body is too hot, the hypothalamus initiates cooling mechanisms like sweating and vasodilation (widening of blood vessels). If it's too cold, it initiates warming mechanisms like shivering and vasoconstriction (narrowing of blood vessels).

39. Describe the neural control of urinary system functions. Urination (micturition) is controlled by a combination of autonomic and somatic signals.

• Storage: As the bladder fills, stretch receptors send signals that inhibit parasympathetic activity and stimulate sympathetic and somatic nerves to keep the sphincters closed.
• Voiding: At an appropriate time, the brain voluntarily relaxes the external sphincter and signals the parasympathetic nervous system to contract the bladder muscle, causing urination.

40. Explain the neural basis of reproductive behavior and hormonal control. The hypothalamus is the key control center, linking the nervous system to the endocrine control of reproduction. It releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary to release hormones (LH and FSH) that act on the gonads. The brain's limbic system is also heavily involved in the motivational and behavioral aspects of reproduction.

41. Describe the stress response pathways and their physiological effects. Stress activates two major pathways:

• SAM System (fast): The sympathetic nervous system stimulates the adrenal medulla to release adrenaline, causing immediate physiological changes like increased heart rate, blood pressure, and glucose mobilization (the "fight or flight" response).
• HPA Axis (slow): The hypothalamus releases CRH, causing the pituitary to release ACTH, which stimulates the adrenal cortex to release cortisol. Cortisol provides a more sustained mobilization of energy and has widespread effects on the body.

42. Explain the neural mechanisms of addiction and tolerance. Addiction involves the brain's dopamine-driven reward pathway. Addictive substances cause a surge of dopamine in the nucleus accumbens, creating a powerful sense of pleasure that reinforces the behavior. Tolerance develops as the brain adapts by reducing its own dopamine receptors or sensitivity. This forces the user to take larger doses to get the same effect and leads to a state of dependence.

43. Describe the effects of various drugs on nervous system function.

• Stimulants (e.g., cocaine): Block the reuptake of dopamine, increasing its levels in the synapse and causing euphoria and alertness.
• Depressants (e.g., alcohol): Enhance the effect of the inhibitory neurotransmitter GABA, leading to sedation and reduced anxiety.
• Opioids (e.g., heroin): Mimic natural endorphins, binding to opioid receptors to produce pain relief and euphoria.

44. Explain the neural basis of learning and conditioning. Learning is based on neuroplasticity, the ability of synapses to change their strength. Long-Term Potentiation (LTP) is a key mechanism where a synapse becomes stronger and more efficient after it is repeatedly stimulated. This strengthening of connections between neurons that fire together is believed to be the cellular basis for forming memories and learned associations (conditioning).

45. Describe the development of language areas and speech control. Language areas, primarily Broca's area (for production) and Wernicke's area (for comprehension), develop in the left hemisphere for most people. During childhood, there is a critical period where the brain is highly plastic and primed to acquire language. Speech control is a complex motor act coordinated by Broca's area, which sends signals to the motor cortex to control the muscles of the lips, tongue, and larynx.

46. Explain the lateralization of brain functions and hemispheric specialization. This is the concept that the two cerebral hemispheres are not identical in function.

• Left Hemisphere: Is typically dominant for language, logic, analytical thought, and mathematical abilities.
• Right Hemisphere: Is typically dominant for spatial awareness, facial recognition, processing music, and interpreting emotional cues. The two hemispheres communicate via the corpus callosum.

47. Describe the neural plasticity and its role in recovery from brain injury. Neuroplasticity is the brain's ability to reorganize its structure and function in response to experience or damage. After an injury like a stroke, the brain can sometimes recover function by having healthy areas take over the functions of the damaged areas. This is the basis for neurorehabilitation, which uses repetitive, task-specific therapy to drive this plastic reorganization.

48. Explain the aging process in nervous system and its consequences. Normal aging involves a modest loss of brain volume, a reduction in the number of synaptic connections, and a decrease in the production of some neurotransmitters. This can lead to slower cognitive processing, mild memory difficulties, and reduced motor coordination. It is distinct from the pathological changes seen in neurodegenerative diseases like Alzheimer's.

49. Describe the common neurodegenerative diseases and their pathophysiology. These are diseases characterized by the progressive death of neurons.

• Alzheimer's Disease: Caused by the accumulation of amyloid plaques and tau tangles, leading to widespread cortical atrophy and dementia.
• Parkinson's Disease: Caused by the death of dopamine-producing neurons in the substantia nigra, leading to motor symptoms like tremor and rigidity.
• Multiple Sclerosis: An autoimmune attack on myelin in the CNS, disrupting nerve signal transmission.

50. Explain multiple sclerosis as an autoimmune disorder affecting myelin. In MS, the body's immune system mistakenly identifies myelin—the protective sheath around axons in the CNS—as a foreign substance and attacks it. This process, called demyelination, leaves scars (scleroses) and disrupts the ability of the nerves to conduct electrical impulses efficiently. This leads to a wide variety of neurological symptoms depending on which nerves are affected.

51. Describe Parkinson's disease and its effects on motor control. Parkinson's disease is caused by the progressive loss of dopamine-producing neurons in a part of the brain called the substantia nigra. Dopamine is crucial for smooth, controlled movement. The lack of dopamine disrupts the function of the basal ganglia, a brain region that controls motor function, leading to the characteristic symptoms of tremor at rest, muscle rigidity, slowness of movement (bradykinesia), and postural instability.

52. Explain Alzheimer's disease and its impact on memory and cognition. Alzheimer's is characterized by the buildup of two abnormal proteins in the brain: amyloid plaques (which accumulate between neurons) and tau tangles (which form inside neurons). These pathologies lead to the widespread death of neurons, particularly in the hippocampus and cerebral cortex. This causes a progressive decline in memory, starting with recent events, and eventually affects all cognitive functions, leading to dementia.

53. Describe epilepsy, its types, and underlying mechanisms. Epilepsy is a disorder characterized by recurrent seizures, which are episodes of abnormal, excessive, and synchronized neuronal activity in the brain. The underlying mechanism is an imbalance between excitatory and inhibitory signals in the brain. Seizures are classified as:

• Focal: Starting in one specific area of the brain.
• Generalized: Involving widespread areas of the brain from the onset.

54. Explain stroke types, risk factors, and neurological consequences.

• Types: Ischemic (caused by a clot blocking a blood vessel) and Hemorrhagic (caused by a vessel rupturing).
• Risk Factors: High blood pressure, smoking, diabetes, high cholesterol.
• Consequences: Depend on the location of the brain damage but commonly include paralysis or weakness on one side of the body (hemiplegia), speech problems (aphasia), and cognitive deficits.

55. Describe spinal cord injuries and their classification based on level and completeness. Spinal cord injuries are classified by:

• Level: The vertebral level of the injury (e.g., C4, T10). Higher injuries affect more of the body.
• Completeness: Complete (total loss of sensory and motor function below the injury) or Incomplete (some function remains). For example, a complete injury in the cervical region causes quadriplegia, while one in the thoracic region causes paraplegia.

56. Explain traumatic brain injury and its acute and chronic effects. A TBI is an injury to the brain caused by an external force. Acute effects can range from brief confusion (concussion) to coma and death. Chronic effects can include long-term problems with cognition (memory, attention), physical function (paralysis, spasticity), and behavior (personality changes, depression), and an increased risk for neurodegenerative diseases.

57. Describe the principles of neurorehabilitation and recovery mechanisms. Neurorehabilitation aims to improve function after a neurological injury. It is based on the principle of neuroplasticity. The primary recovery mechanism is inducing the brain to reorganize itself through highly repetitive, intensive, and task-specific training. This encourages healthy brain areas to take over the functions of damaged areas and strengthens remaining neural pathways.

58. Explain the diagnostic techniques used in neurology.

• Neuroimaging: CT scans and MRI scans visualize brain structure to find tumors, strokes, or atrophy.
• Electrophysiology: EEG records brain electrical activity to diagnose epilepsy. Nerve conduction studies (NCS) and EMG assess peripheral nerve and muscle function.
• Lumbar Puncture: Analysis of cerebrospinal fluid can detect infection, inflammation, or cancer.

59. Describe the electroencephalography and its clinical applications. An EEG is a recording of the brain's spontaneous electrical activity from the scalp. It shows brain wave patterns. Its main clinical applications are:

• Diagnosing and classifying epilepsy by detecting abnormal seizure activity.
• Evaluating sleep disorders by identifying sleep stages.
• Monitoring brain function in comatose patients or during surgery.

60. Explain neuroimaging techniques and their uses in diagnosis.

• Structural Imaging: CT is fast and used for acute trauma or stroke to detect bleeding. MRI provides high-resolution images of soft tissue, making it ideal for detecting tumors, inflammation (like in MS), or subtle structural changes.
• Functional Imaging: fMRI and PET scans measure brain activity by tracking changes in blood flow or metabolism. They are used more in research but can help localize seizure focus or assess brain viability.

61. Describe nerve conduction studies and electromyography.

• Nerve Conduction Study (NCS): Measures the speed and strength of electrical signals traveling down a peripheral nerve in response to a small electrical stimulus. It is used to diagnose nerve damage or entrapment (e.g., carpal tunnel syndrome).
• Electromyography (EMG): Records the electrical activity produced by muscles, using a needle electrode. It helps differentiate between muscle and nerve disorders.

62. Explain the lumbar puncture procedure and CSF analysis. A lumbar puncture (spinal tap) is a procedure where a needle is inserted into the lower back (lumbar region) to collect a sample of cerebrospinal fluid (CSF). CSF analysis is used to diagnose conditions affecting the CNS. For example, the presence of white blood cells suggests infection (meningitis), while specific proteins can indicate inflammation (MS) or cancer.

63. Describe the mechanisms of action of local anesthetics. Local anesthetics (like lidocaine) work by blocking nerve signal transmission in a specific area. They do this by physically blocking voltage-gated sodium channels on the neuron's membrane. This prevents sodium from entering the cell, thereby preventing the generation of an action potential (nerve impulse), so pain signals cannot be sent to the brain.

64. Explain general anesthesia and its effects on consciousness. General anesthesia induces a reversible, medically controlled coma. The exact mechanism is complex, but it is thought to work by enhancing the activity of inhibitory neurotransmitters (like GABA) and reducing the activity of excitatory neurotransmitters throughout the brain. This widespread depression of CNS activity, particularly in the thalamus and reticular formation, leads to a loss of consciousness, sensation, and memory.

65. Describe analgesic drugs and their mechanisms of pain relief. Analgesics are pain relievers.

• Opioids (e.g., morphine): Act on the CNS by binding to opioid receptors, mimicking the effect of endorphins to block the transmission of pain signals.
• NSAIDs (e.g., ibuprofen): Act on the peripheral nervous system at the site of injury. They reduce pain and inflammation by inhibiting the cyclooxygenase (COX) enzymes, which prevents the production of pain-producing chemicals called prostaglandins.

66. Describe anticonvulsant drugs and their use in epilepsy treatment. Anticonvulsant (or anti-seizure) drugs are used to treat epilepsy by preventing or reducing the frequency of seizures. They work through several mechanisms to decrease the excessive electrical activity in the brain, such as:

• Blocking sodium channels to reduce neuronal firing.
• Enhancing the effects of the inhibitory neurotransmitter GABA.
• Blocking calcium channels.

67. Describe antiparkinsonian drugs and dopamine replacement therapy. Antiparkinsonian drugs aim to restore the balance of dopamine in the brain, which is depleted in Parkinson's disease. The most common strategy is dopamine replacement therapy. Since dopamine itself cannot cross the blood-brain barrier, patients are given its precursor, Levodopa (L-DOPA), which can enter the brain and be converted into dopamine by neurons.

68. Explain psychoactive drugs and their effects on neurotransmission. Psychoactive drugs are substances that alter brain function, resulting in changes in perception, mood, or consciousness. They work by interfering with neurotransmission. They can:

• Mimic neurotransmitters (agonists).
• Block neurotransmitter receptors (antagonists).
• Alter the release or reuptake of neurotransmitters (e.g., SSRIs block serotonin reuptake).

69. Describe antidepressants and their mechanisms of action. Antidepressants are used to treat depression and anxiety disorders. Most work by increasing the levels of certain neurotransmitters (monoamines) in the brain.

• SSRIs (Selective Serotonin Reuptake Inhibitors): The most common type, they specifically block the reabsorption of serotonin, increasing its availability in the synapse.
• SNRIs: Block the reuptake of both serotonin and norepinephrine.

70. Explain anxiolytic drugs and their effects on GABA transmission. Anxiolytics are anti-anxiety drugs. The most common class is benzodiazepines (e.g., Valium, Xanax). They work by enhancing the effect of GABA, the brain's primary inhibitory neurotransmitter. By binding to GABA receptors, they make the neuron more responsive to GABA, which increases the flow of chloride ions into the neuron, hyperpolarizes it, and makes it less likely to fire, resulting in a calming effect.

71. Describe stimulants and their effects on arousal and attention. Stimulants (e.g., amphetamines, caffeine) increase CNS activity. They typically work by increasing the levels of dopamine and norepinephrine. This enhances alertness, attention, and energy, which is why they are used to treat ADHD. However, they can also cause restlessness, anxiety, and have a high potential for abuse.

72. Explain the neurotoxic effects of alcohol on nervous system. Chronic heavy alcohol use is neurotoxic and can cause widespread brain damage. Alcohol is a CNS depressant that enhances GABA's inhibitory effects and blocks the excitatory effects of glutamate. Long-term use can lead to brain shrinkage (atrophy), neuronal death, memory loss (Wernicke-Korsakoff syndrome), and damage to the cerebellum, causing problems with balance and coordination.

73. Describe the effects of caffeine and nicotine on brain function.

• Caffeine: Acts as a stimulant by blocking adenosine receptors. Adenosine is a neurotransmitter that promotes sleepiness, so by blocking it, caffeine increases alertness and reduces fatigue.
• Nicotine: Acts as a stimulant by binding to and activating nicotinic acetylcholine receptors. This leads to the release of many neurotransmitters, including dopamine, which causes its rewarding and addictive effects.

74. Explain the neural mechanisms of circadian rhythm disorders. These disorders occur when the body's internal clock (the SCN in the hypothalamus) is not aligned with the external environment. This can be caused by:

• External factors: Jet lag or shift work.
• Internal factors: Genetic mutations affecting the clock genes, or damage to the SCN. The result is a mismatch between the desired and actual sleep-wake times, leading to insomnia and daytime sleepiness.

75. Describe sleep disorders and their neurological basis.

• Insomnia: Difficulty falling or staying asleep, often linked to hyperarousal of the nervous system.
• Sleep Apnea: Repeatedly stopping breathing during sleep, caused by a physical obstruction or a failure of the brainstem to control respiration.
• Narcolepsy: Characterized by excessive daytime sleepiness and sudden attacks of sleep, caused by a loss of hypothalamic neurons that produce the wakefulness-promoting neurotransmitter orexin.

76. Explain attention deficit hyperactivity disorder (ADHD) and its neural basis. ADHD is a neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity. It is thought to be related to dysfunction in the prefrontal cortex and basal ganglia, and an imbalance in the neurotransmitters dopamine and norepinephrine, which are crucial for regulating attention, motivation, and executive function.

77. Describe autism spectrum disorders and their neurological features. ASD is a complex neurodevelopmental disorder characterized by challenges with social communication and interaction, and restricted, repetitive behaviors. Neurological features are varied but can include differences in brain growth patterns (early overgrowth), altered connectivity between brain regions, and imbalances in excitatory and inhibitory neurotransmission. There is a strong genetic component.

78. Explain schizophrenia and its neurobiological aspects. Schizophrenia is a severe psychiatric disorder characterized by psychosis (hallucinations, delusions), disorganized thought, and negative symptoms (e.g., lack of motivation). It is strongly associated with excess dopamine activity in certain brain pathways (the dopamine hypothesis). Other neurobiological aspects include reduced brain volume, particularly in the prefrontal cortex, and dysfunction in glutamate neurotransmission.

79. Describe depression and its neurochemical basis. Major depressive disorder is characterized by persistent low mood and loss of interest or pleasure. The monoamine hypothesis suggests it is caused by a deficiency in the brain of certain neurotransmitters, primarily serotonin, norepinephrine, and dopamine. Modern theories also emphasize the role of stress, inflammation, and reduced neuroplasticity, particularly in the hippocampus and prefrontal cortex.

80. Explain anxiety disorders and their neural substrates. Anxiety disorders are characterized by excessive fear and worry. The amygdala, the brain's fear center, is often hyperactive in these disorders. There is also thought to be an imbalance in neurotransmitters, particularly low levels of the inhibitory neurotransmitter GABA and dysregulation of serotonin and norepinephrine. The prefrontal cortex, which normally helps regulate the amygdala, may be underactive.

81. Describe post-traumatic stress disorder and its brain changes. PTSD can develop after exposure to a traumatic event and is characterized by intrusive memories, avoidance, and hyperarousal. Brain changes include a hyperactive amygdala (leading to an exaggerated fear response), an underactive prefrontal cortex (reducing the ability to control fear), and a smaller hippocampus (which can affect memory consolidation and context).

82. Explain the neural basis of personality disorders. Personality disorders involve enduring patterns of inner experience and behavior that deviate from cultural expectations. The neural basis is complex but is thought to involve dysfunction in brain circuits that regulate emotion and impulse control. For example, borderline personality disorder is associated with a hyperactive amygdala and reduced prefrontal cortex control, leading to emotional instability and impulsivity.

83. Describe the effects of meditation on brain structure and function. Consistent meditation practice has been shown to produce measurable changes in the brain. Functionally, it can reduce activity in the amygdala (reducing stress) and strengthen connections in the prefrontal cortex (improving attention and emotional regulation). Structurally, it has been linked to increased grey matter thickness in areas related to self-awareness and introspection, like the insula and prefrontal cortex.

84. Explain the benefits of physical exercise for nervous system health. Exercise has profound benefits for the brain. It increases blood flow, delivering more oxygen and nutrients. It also stimulates the release of brain-derived neurotrophic factor (BDNF), a protein that supports the survival of existing neurons and encourages the growth of new ones (neurogenesis), particularly in the hippocampus. This can improve learning, memory, and mood, and reduce the risk of neurodegenerative disease.

85. Describe the role of nutrition in maintaining nervous system function. The brain requires a constant supply of energy (glucose) and specific nutrients to function. Omega-3 fatty acids are crucial components of neuronal membranes. B vitamins are essential for producing neurotransmitters. Antioxidants (found in fruits and vegetables) help protect the brain from oxidative stress. Poor nutrition can impair cognitive function and increase the risk of neurological problems.

86. Explain the effects of environmental toxins on nervous system development. Environmental neurotoxins can severely disrupt brain development. For example:

• Lead: Can cause widespread neuronal damage, leading to learning disabilities and a lower IQ.
• Mercury: Can cause severe damage to the cerebellum and cortex, leading to motor and cognitive impairments.
• Alcohol (in utero): Can cause Fetal Alcohol Syndrome, characterized by brain damage and lifelong developmental problems.

87. Describe the neural mechanisms of chronic pain syndromes. Chronic pain syndromes (like fibromyalgia or neuropathic pain) are often caused by changes in the nervous system itself, a process called central sensitization. The nervous system becomes hypersensitive, amplifying pain signals and interpreting normal sensations as painful. This involves long-term changes in the connectivity and function of neurons in the spinal cord and brain, making pain persist long after an initial injury has healed.

88. Explain phantom limb pain and its neurological basis. Phantom limb pain is the sensation of pain in a limb that has been amputated. It is believed to be caused by maladaptive neuroplasticity in the brain. The area of the somatosensory cortex that used to receive input from the missing limb becomes deprived of signals. This cortical area can then be invaded by signals from adjacent cortical areas, and the brain misinterprets this new activity as pain coming from the missing limb.

89. Describe migraine headaches and their neural mechanisms. Migraines are a complex neurological disorder, not just a simple headache. The leading theory is that they are caused by a wave of abnormal electrical activity in the brain called cortical spreading depression. This wave triggers inflammation and the release of pain-producing chemicals that sensitize pain pathways in the trigeminal nerve, which innervates the head and face, leading to severe, throbbing pain.

90. Explain the neural control of immune system function. The nervous and immune systems are closely linked. The brain, particularly through the hypothalamus and the autonomic nervous system, can influence immune function. For example, the sympathetic nervous system can release norepinephrine, which can affect the activity of immune cells. Chronic stress, acting through the HPA axis, can suppress the immune system by the prolonged release of cortisol.

91. Describe the gut-brain axis and its physiological significance. The gut-brain axis is the two-way communication link between the central nervous system and the enteric nervous system of the gut. This communication occurs through the vagus nerve, hormones, and the immune system. Its significance is that the gut microbiome can influence brain function and mood, and conversely, the brain (e.g., through stress) can influence gut health and function.

92. Explain the neural mechanisms of appetite and weight regulation. Appetite is regulated by the hypothalamus, which integrates signals from the body to control hunger and satiety. Hormones play a key role:

• Ghrelin (from the stomach) stimulates hunger.
• Leptin (from fat cells) and Insulin signal satiety (fullness). Disruptions in these hypothalamic circuits can lead to obesity or eating disorders.

93. Describe the role of nervous system in thermal regulation. The hypothalamus acts as the body's thermostat. It contains specialized neurons that sense the temperature of the blood. If the temperature deviates from the set point (around 37°C or 98.6°F), the hypothalamus orchestrates autonomic responses to either generate heat (shivering, vasoconstriction) or dissipate heat (sweating, vasodilation) to restore the normal body temperature.

94. Explain the neural control of water and electrolyte balance. The hypothalamus also controls water balance. It contains osmoreceptors that detect the concentration of solutes in the blood. If the blood becomes too concentrated (dehydration), the hypothalamus triggers the sensation of thirst and also releases antidiuretic hormone (ADH) from the pituitary gland. ADH acts on the kidneys to conserve water.

95. Describe the integration of nervous and endocrine systems in maintaining homeostasis. The nervous and endocrine systems are tightly integrated, primarily through the hypothalamus-pituitary axis, to maintain homeostasis. The hypothalamus acts as the link, receiving neural signals from the brain and body, and in response, it controls the pituitary gland. The pituitary, in turn, releases hormones that regulate other endocrine glands. This allows for rapid neural control to be coordinated with slower, more sustained hormonal control.

96. Explain the neural mechanisms underlying consciousness and awareness. Consciousness is a complex phenomenon with no single location in the brain. It is thought to arise from the large-scale, synchronized firing of neurons across widespread brain networks, particularly involving the thalamus, cortex, and the reticular activating system in the brainstem. The thalamo-cortical loops are believed to be essential for binding together different sensory experiences into a unified, conscious whole.

97. Describe the evolutionary development of nervous system complexity across species. Evolution shows a trend towards increasing nervous system complexity and centralization. Simple invertebrates may only have a diffuse nerve net. More complex invertebrates (like insects) have a ventral nerve cord and ganglia that function as simple brains. In vertebrates, there is a clear trend towards encephalization—an increase in the size and complexity of the brain, particularly the forebrain and cerebral cortex, allowing for more advanced cognitive abilities.

98. Explain the role of glial cells in supporting neuronal function and brain health. Glial cells are more than just passive support cells. Astrocytes form the blood-brain barrier, provide nutrients to neurons, and regulate the chemical environment. Oligodendrocytes and Schwann cells produce the myelin sheath essential for fast nerve conduction. Microglia act as the brain's immune cells, cleaning up debris and fighting infection. Glial cells are critical for neuronal health, synaptic function, and overall brain homeostasis.

99. Describe the future directions in neuroscience research and potential therapeutic applications. Future research is focused on areas like optogenetics (using light to control neurons), advanced neuroimaging, and understanding the brain's connectome (the complete map of neural connections). Potential therapeutic applications are vast, including developing more targeted treatments for neurodegenerative diseases, creating brain-computer interfaces to restore lost function, and finding new ways to treat psychiatric disorders by modulating specific neural circuits.

100. Describe the future directions in neuroscience research and potential therapeutic applications. Future research is focused on areas like optogenetics (using light to control neurons), advanced neuroimaging, and understanding the brain's connectome (the complete map of neural connections). Potential therapeutic applications are vast, including developing more targeted treatments for neurodegenerative diseases, creating brain-computer interfaces to restore lost function, and finding new ways to treat psychiatric disorders by modulating specific neural circuits.