Question

During the rapid ventricular filling phase, venous pressure ________ and aortic pressure ________.

a) Increases, decreases
b) Decreases, increases
c) Increases, increases
d) Decreases, decreases

Answer 1

During the rapid ventricular filling phase, both venous pressure and aortic pressure decrease, as ventricles relax and blood flows back toward the heart.

Step-by-step explanation:

During the rapid ventricular filling phase, venous pressure decreases and aortic pressure decreases. This occurs because the ventricular muscle relaxes, causing pressure within the ventricles to fall. When the pressure within the ventricles drops below the pressure in the pulmonary trunk and aorta, blood flows back toward the heart, indicated by the dicrotic notch on blood pressure tracings. The semilunar valves close to prevent backflow into the heart, and since the atrioventricular valves remain closed, no blood enters the ventricle, leading to the isovolumic ventricular relaxation phase. Consequently, venous pressure is reduced to facilitate the return of blood to the heart, while aortic pressure decreases after the ejection of blood during systole.