KVPY Sample Paper KVPY Stream-SX Model Paper-27

What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL?

A) 50 beats per minute

B) 75 beats per minute

C) 100 beats per minute

D) 125 beats per minute

Correct Answer: C

Solution :

Cardiac output = Stroke volume\[\times \]Heart rate

\[\Rightarrow \] Cardiac output \[=5L\]or\[5000\text{ }ml\]

\[\Rightarrow \] Blood volume in ventricles at the end of diastole\[=100\text{ }ml\]

\[\Rightarrow \] Blood volume in ventricles at the end of systole \[=50ml\]

Stroke volume \[=100-50\] \[=50ml.\]

So, \[5000\text{ }ml=50\text{ }ml\times Heart\text{ }rate\]

So, Heart rate\[=100\]beats per minute.