Question

Identify the correct statement regarding cardiac activity.

• A. Normal activities of the human heart is regulated intrinsically, hence it is neurogenic.
• B. A special neural centre in the medulla oblongata can moderate the cardiac function through CNS.
• C. Parasympathetic neural signals increase the rate of heart beat.
• D. Adrenal medullary hormones can increase cardiac output.
• E. The end of the T-wave marks the end of diastole.

Answer 1

Answer: (D)

Adrenal medullary hormones can increase cardiac output.

A. Normal activities of human heart are regulated intrinsically and hence it is myogenic which means that impulses for contraction are originated in the muscles itself.

B. A special neural centre in the medulla oblongata called cardiovascular centre, can moderate the cardiac functions through ANS (Autonomous nervous system).

C. Sympathetic neural signals increase the rate of heart beat due to secretion of adrenaline from adrenal medulla which activates sympathetic nervous system.

D. Adrenal medulla secrete adrenaline and nor adrenaline hormones which can increase cardiac output because they increase heart beat and strength of heart contraction.

E. The end of T wave marks the end of systole. T wave in ECG represents ventricular repolarisation.

Hence, statement D is correct.

So, the correct answer is 'Adrenal medullary hormones can increase cardiac output'.