Why are there atrial and ventricular systole and diastole?

Accordingly, when the heart chambers are relaxed (diastole), blood will flow into the atria from the veins, which are higher in pressure. When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles.

Why does the second heart sound occur after the T wave?

The second heart sound, called S2, makes a “dub” sound caused by the closure of the semilunar (aortic and pulmonary) valves following ventricular systole. S2 is split because aortic valve closure occurs before pulmonary valve closure.

Why do both atria contract simultaneously?

Each chamber has a one-way valve at its exit that prevents blood from flowing backwards. In the first stage the Right and Left Atria contract at the same time, pumping blood to the Right and Left Ventricles. Then the Ventricles contract together (called systole) to propel blood out of the heart.

Which of the following occurs when the aortic and mitral valves are both closed?

Ventricular pressure then declines exponentially during isovolumetric relaxation, when both the aortic and mitral valves are closed. This begins the ventricular diastole. When ventricular pressure declines below left atrial pressure, the mitral valve opens and ventricular filling begins.

When both atria and both ventricles are and relaxed face the condition is called?

During “joint diastole” phase of cardiac cycle both the atria (auricles) and ventricles are relaxed simultaneously.

Why does the second heart sound occur after the T wave 4 pts?

The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2). The closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10 mmHg on the right.

What occurs during the time between the first heart sound and the second heart sound?

Assorted References. Closure of the heart valves is associated with an audible sound, called the heartbeat. The first sound occurs when the mitral and tricuspid valves close, the second when the pulmonary and aortic semilunar valves close.

Why do both ventricles contract at the same time?

The biventricular pacemaker has leads implanted in the right atria, the right ventricle and the coronary sinus to sense and pace the left ventricle. This three-lead system allows the pacemaker to sense both ventricles and stimulate in a way that causes them to contract together.

Do both ventricles contract simultaneously?

While it is convenient to describe the flow of blood through the right side of the heart and then through the left side, it is important to realize that both atria and ventricles contract at the same time. The heart works as two pumps, one on the right and one on the left, working simultaneously.