ANATOMY

Detailed explanation-1: -The period of relaxation is called diastole. The period of contraction is called systole. Diastole is the longer of the two phases so that the heart can rest between contractions.

Detailed explanation-2: -Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contraction.

Detailed explanation-3: -Diastole is the period of the cardiac cycle that encompasses ventricular relaxation, passive and active filling of blood into the heart, and the period just prior to ejection. At the cellular level, the interplay of calcium within the cardiac myocytes is crucial to ventricular relaxation.

Detailed explanation-4: -filling occurs during diastole, which has 4 phases: (1) isovolumic relaxation; (2) rapid filling phase; (3) slow filling, or diastasis; and (4) final filling during atrial systole (atrial kick.) Isovolumic relaxation – this phase occurs after the aortic valve closes and the mitral valve is still closed.

Detailed explanation-5: -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.