Answer: 72 beats per minute.
- A 50 beats per minute
- B 72 beats per minute
- C 100 beats per minute
- D 120 beats per minute
Correct answer: B. 72 beats per minute
Explanation: Cardiac output equals stroke volume times heart rate, so 70 mL times about 72 beats per minute gives approximately 5000 mL, or 5 litres, per minute.
A single ECG cycle: the P wave marks atrial depolarisation (contraction signal), the large QRS complex marks ventricular depolarisation, and the T wave marks ventricular repolarisation (recovery) before the next cycle begins.
Concept context
Blood, lymph, the heart, the cardiac cycle, blood pressure, and ECG. High NEET weightage.