AP BIOLOGY

Detailed explanation-1: -The total period of the cardiac cycle is 0.8 seconds which includes a cardiac diastole of 0.4 seconds, a ventricular systole of 0.3 seconds and an atrial systole of 0.1 seconds.

Detailed explanation-2: -Duration of Cardiac Cycle At a heartbeat 72 beats/minute, duration of each cardiac cycle will be 0.8 seconds.

Detailed explanation-3: -The normal duration of the cardiac cycle is 0.8 second.

Detailed explanation-4: -Atrial systole: lasts about 0.1 seconds-both atria contract and force the blood from the atria into the ventricles. Ventricular systole: lasts about 0.3 seconds-both ventricles contract, blood is forced to the lungs via the pulmonary trunk, and the rest of the body via the aorta.

Detailed explanation-5: -There is an inverse relationship between the duration of cardiac cycle and heart rate. Hence when the heart rate is increased to 120 beats per minute, the cardiac cycle duration will be about 0.5 sec.