The Frank-Starling law of the heart states that

Correct Answer: A

Rationale: The Frank-Starling law describes how increased preload (end-diastolic volume) enhances the force of ventricular contraction.

Correct Answer: C

Rationale: Lifestyle modifications usually include restricting sodium and fat intake, increasing intake of fruits and vegetables, and implementing regular physical activity. There is no need to increase calcium, potassium, and vitamin intake. Calorie restriction may be required for some patients, but a specific reduction in protein and carbohydrates is not normally indicated.

Correct Answer: A

Rationale: Nitric oxide inhibits gene transcription for endothelin-1 secretion through various signaling pathways.

Correct Answer: D

Rationale: The largest drop in energy actually occurs across the arterioles, not the precapillary sphincters.

Correct Answer: D

Rationale: The cardiac cycle encompasses all the events associated with one complete heartbeat, including systole and diastole of both atria and ventricles.