Question

Choose the correct answer from the alternatives given.
Blood enters the heart because muscles of:

• A. atria relax
• B. ventricles relax
• C. atria contract
• D. ventricles contract

Answer 1

The correct option is A atria relax

Human blood passes from the inferior vena cava into the diastolic right atrium of the heart because of a pressure differential between the atrium and the vena cava. This negative pressure gradient is created by atrial diastole and pulls blood to the atrium which is then pumped to the ventricles by contraction.

So, the correct answer is atria relax.