Question

Heartbeat is controlled by

• A. nerves only
• B. enzymes only
• C. hormones only
• D. both nerves and hormones

Answer 1

The correct option is D

both nerves and hormones

The correct option is D.\

Explanation for correct option:

1. Heartbeat is controlled by the two branches of the autonomic (involuntary) nervous system.
2. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).
3. The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate.

Final answer: Heartbeat is controlled by both nerves and hormones.