Question

Which of the following is associated with decrease in cardiac output?

(1) Adrenal medullary hormones

(2) Sympathetic nerves

(3) Parasympathetic neural signals

(4) Pneumotaxic centre

Answer 1

Answer (3) Parasympathetic neural signals

Sol. Option (3) is the correct answer. Parasympathetic neural signals decrease the rate of heart beat, speed of conduction of action potential, stroke volume and thereby the cardiac output.

Adrenal medullary hormones increase cardiac output.

Sympathetic neural signals increase the rate of heart beat, strength of ventricular contraction and thereby the cardiac output.