- A Heart rate rises proportionally with sympathetic stimulation during physical exercise
- B Greater cardiac filling → greater stretch of ventricle → greater force of contraction
- C The heart ejects a fixed stroke volume regardless of venous return changes
- D Arterial blood pressure directly sets the intrinsic rate of SA node firing each beat
Correct answer: B. Greater cardiac filling → greater stretch of ventricle → greater force of contraction
Explanation: Frank-Starling law: the more ventricular muscle is stretched by filling (preload), the greater the subsequent contraction force and stroke volume.
Concept context
Blood, lymph, the heart, the cardiac cycle, blood pressure, and ECG. High NEET weightage.