Describe in detail the names of the stages and the events that occur during each stage of the cardiac cycle.

The cardiac cycle incorporates all the physiological occurrences related to a single heartbeat, comprising mechanical events, electrical events, and sounds of heart. The cardiac cycle is basically differentiated into two stages, that is, diastole or the relaxation stage, and systole or the contraction stage.

However, each of these stages is further differentiated into a ventricular and atrial component. The cardiac cycle, thus, comprises four stages:

a. Atrial systole: It takes place for approximately 0.1 seconds, in this the blood is forced into the ventricles from the atria due to contraction of both the atria.

b. Ventricular systole: It has a duration of 0.3 seconds. In this, blood is forced into the lungs through the pulmonary trunk, and to the remaining parts of the body through the aorta due to contraction of both the ventricles.

c. Arial diastole: It last for 0.7 seconds, in this relaxation of atria takes place, which allows it to get filled with blood through vena cavae, that is, the large veins.

d. Ventricular diastole: It lasts for 0.5 seconds, It initiates prior to atrial systole, and permits the ventricles to get filled with blood passively from the atria.