Question

Read the following statements :
A. The action potential generated by the SA node stimulates both ventricles to undergo simultaneous contraction.
B. The heart sound Lubb is associated with the closure of both semilunar valves.
C. The QRS complex in ECG represents the depolarization of the ventricles.
Select the appropriate option from the following :

Answer 1

Answer:

Correct option is D)

A. Pacemaker of heart is Sinoatrial node located in right atrium. It generates impulses which lead to contraction of atria.

B. Lubb is the first sound of heart beat and produced due to closure of atrioventricular valves.

C. Stroke volume is the amount of blood delivered to heart by the veins. In each cardiac cycle stroke volume is about 70ml of blood.

D. QRS complex in an ECG represents depolarisation of ventricles which initiates contraction of ventricles.

E. The opening between right atrium and right ventricle is guarded by tricuspid valve.

Hence, statement D is correct.

So, the correct answer is 'QRS complex in an ECG indicates depolarisation of ventricles'.