Numerical Problems/ISC/Class 11
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Numerical Problems - Body Fluids and Circulation
Q1: A person has a heart rate of 75 beats per minute. Calculate the duration of their cardiac cycle.
Solution: The duration of one cardiac cycle is the reciprocal of the heart rate. Duration = 60 seconds / Heart Rate Duration = 60 / 75 = 0.8 seconds.
Q2: If a cardiac cycle is 0.8 seconds long, and the ventricular systole lasts for 0.3 seconds, what is the duration of ventricular diastole?
Solution: Total cycle duration = Ventricular Systole + Ventricular Diastole 0.8 s = 0.3 s + Ventricular Diastole Ventricular Diastole = 0.8 - 0.3 = 0.5 seconds.
Q3: In a normal cardiac cycle of 0.8s, atrial systole is 0.1s, and ventricular systole is 0.3s. Calculate the duration of joint diastole.
Solution: Joint diastole is the period when both atria and ventricles are relaxed. The total duration of the cardiac cycle is 0.8s. The heart is in some form of systole for 0.1s (atria) + 0.3s (ventricle) = 0.4s. The rest of the time it is in joint diastole. Joint Diastole = 0.8s - 0.4s = 0.4s.
A person has a stroke volume of 70 mL/beat and a heart rate of 72 beats/minute. Calculate their cardiac output in liters per minute.
Solution:
Cardiac Output (CO) is the volume of blood pumped by the heart per minute. It is calculated by multiplying the stroke volume by the heart rate.
Cardiac Output = Stroke Volume x Heart Rate Cardiac Output = 70 mL/beat * 72 beats/minute Cardiac Output = 5040 mL/minute
To convert milliliters to liters, divide by 1000: Cardiac Output = 5040 mL/minute / 1000 mL/L = 5.04 L/minute
Therefore, the person's cardiac output is 5.04 liters per minute.
A person's blood pressure reading is 120/80 mmHg. What do these two numbers represent?
Solution:
This reading indicates a normal blood pressure.
If a person's blood pressure is 140/90 mmHg, what is their pulse pressure?
Solution:
Pulse pressure is the difference between the systolic and diastolic blood pressure.
Pulse Pressure = Systolic Pressure - Diastolic Pressure Pulse Pressure = 140 mmHg - 90 mmHg Pulse Pressure = 50 mmHg
A normal pulse pressure is typically between 40-60 mmHg.
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