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  4. How many values are correctly given from following? i. Normal heartbeat rate = 72 beats/min. ii. Period of cardiac cycle = 0.8 sec. iii. Stroke volume = 70 ml iv. Normal cardiac output = 5000 ml v. Normal blood pressure = 120/80 mm Hg

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Q. How many values are correctly given from following?
i. Normal heartbeat rate = 72 beats/min.
ii. Period of cardiac cycle = 0.8 sec.
iii. Stroke volume = 70 ml
iv. Normal cardiac output = 5000 ml
v. Normal blood pressure = 120/80 mm Hg

NTA AbhyasNTA Abhyas 2022

Solution:

The heart beats 72 times per minute, i.e., those many cardiac cycles are performed per minute. From this, it could be deduced that the duration of a cardiac cycle is 0.8 seconds. During a cardiac cycle, each ventricle pumps out approximately 70 mL of blood which is called the stroke volume. The stroke volume multiplied by the heart rate (no. of beats per min.) gives the cardiac output. Therefore, the cardiac output can be defined as the volume of blood pumped out by each ventricle per minute and averages 5000 mL or 5 litres in a healthy individual. The body has the ability to alter the stroke volume as well as the heart rate and thereby the cardiac output. Hypertension is the term for blood pressure that is higher than normal (120/80). In this measurement, 120 mm Hg (millimetres of mercury pressure) is the systolic, or pumping, pressure and 80 mm Hg is the diastolic, or resting, pressure.