Question

Choose the correct answer from the alternatives given.
Human blood passes from the inferior vena cava into the diastolic right atrium of the heart
because of:

• A. the pushing of venous valves
• B. a pressure differential between the atrium and the vena cava
• C. the beating of the SA node
• D. gravitational pull

Answer 1

The correct option is B a pressure differential between the atrium and the vena cava

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 pulls blood to the atrium which is then pumped to the ventricles by contraction.

So, the correct option is 'a pressure differential between the atrium and the vena cava'.