Question

When the parasympathetic nerve supply to the heart is disturbed, the heart rate will

• A. Decrease
• B. Increase
• C. Heart stops
• D. Heart beats without nervous control

Answer 1

The correct option is B

Increase

The correct option is B.

Explanation of the correct option:

1. The parasympathetic nerve supply is a part of the autonomous nervous system which is involved in re-establishing normal situations after any aggressive act.
2. The parasympathetic nervous system is responsible for a resting heartbeat rate which is about 70 beats per minute.
3. In the absence of disturbing nervous system control, the heartbeat would increase and reach about 100 times per minute.

Explanation of the incorrect options:

Option A:

The heart rate will decrease if there is some abnormality with the sympathetic nervous system.

Option C:

A heart stops working when there is a problem with the heart's electrical system.

Option D:

A heart does not beat normally without nervous control.

Final answer: When the parasympathetic nerve supply to the heart is disturbed, the heart rate will increase.