Question

How do parasympathetic neural signals affect the working of the heart ?

• A. Reduce both heart rate and cardiac output
• B. Heart rate is increased without affecting the cardiac output
• C. Both heart rate and cardiac output increase
• D. Heart rate decreases but cardiac output increases

Answer 1

The correct option is A Reduce both heart rate and cardiac output

Cardiac function is moderated by a neural centre in the medulla oblangata through autonomic nervous system (ANS). Neural signals through parasympathetic nerves can decrease the rate of heart beat, decreases the speed of conduction of action potential and thereby decreases the cardiac output.

The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate.

Parasympathetic neural signal reduces both heart rate and cardiac output, through the postganglionic fibres. These fibres are very short and are cholinergic in nature.

Thus, the correct answer is "option a"