CVS Practice Test

The left ventricle primarily receives its blood supply during diastole. During this phase, the heart muscle relaxes, allowing the coronary arteries, which branch off from the aorta, to fill with blood. This is critical because the left ventricle is responsible for pumping oxygenated blood to the rest of the body, so it requires a substantial blood supply for proper oxygenation and nutrient delivery to the cardiac tissue itself.

During systole, when the heart contracts, the aortic valve opens, and blood is pumped out of the left ventricle into the aorta, which can lead to a decrease in the filling of the coronary arteries. Thus, while the heart is actively pumping blood, there is less opportunity for the coronary arteries to receive blood flow.

The idea that blood supply could come during both systole and diastole equally is misleading because coronary perfusion is significantly enhanced during diastole when the heart muscle is not contracting and the vessels can fill more effectively.

Atrial contraction does contribute to the filling of the ventricles, but it is not the primary time when the left ventricle receives its blood supply. Instead, it is the state of relaxation in diastole that allows for optimal coronary artery filling and oxygen