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NEET-XII-Biology

P1 year:2019

with Solutions - page 3
Qstn# 130 Prvs-QstnNext-Qstn
  • #130
    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?
    (1) 50 beats per minute
    (2) 75 beats per minute
    (3) 100 beats per minute
    (4) 125 beats per minute
    digAnsr:   3
    Ans : (3)
    Sol. Cardiac output = stroke volume × Heart rate
    &implies; Cardiac output = 5L or 5000 ml
    &implies; Blood volume in ventricles at the end of
    diastole = 100 ml
    &implies; Blood volume in ventricles at the end of
    systole = 50 ml
    Stroke volume = 100 - 50
    = 50 ml.
    So,
    5000 ml = 50 ml × Heart rate
    So, Heart rate = 100 beats per minute.