Question
Biology Question on body fluids and circulation
In humans blood passes from post caval to the diastolic right atrium of heart due to
A
Stimulation of the sino-auricular node
B
Pressure difference between the post caval and atrium
C
Pushing open of the venous valves
D
Suction pull
Answer
Pressure difference between the post caval and atrium
Explanation
Solution
Blood passes from the superior and inferior vana cava into the right atrium. During the start of diastole, the pressure drops in the right atrium, thereby forcing the blood from vena cava to enter the right atrium. During diastole as the atrium relaxes and enlarges in size, the pressure falls.