ANATOMY

Detailed explanation-1: -Both the atria and the ventricles undergo alternating states of systole and diastole. In other words, when the atria are in diastole, the ventricles are in systole and vice versa.

Detailed explanation-2: -During ventricular contraction, the atria relax (atrial diastole) and receive venous return from both the body and the lungs. Then, in ventricular diastole, the lower chambers relax, allowing initial passive filling of the thick-walled ventricles and emptying of the atria.

Detailed explanation-3: -The cardiac cycle is essentially split into two phases, systole (the contraction phase) and diastole (the relaxation phase). Each of these is then further divided into an atrial and ventricular component.

Detailed explanation-4: -Cardiac cycle events can be divided into diastole and systole. Diastole represents ventricular filling, and systole represents ventricular contraction/ejection.

Detailed explanation-5: -During ventricular systole the ventricles are contracting and vigorously pulsing (or ejecting) two separated blood supplies from the heart-one to the lungs and one to all other body organs and systems-while the two atria are relaxed (atrial diastole).