Explain contraction and relaxation of heart(distole and systole)

Diastolic pressure occurs near the beginning of the cardiac cycle. It is the minimum pressure in the arteries when the pumping chambers of the heart — ventricles — fill with blood. Near the end of the cardiac cycle, systolic pressure, or peak pressure, occurs when the ventricles contract.
As the heart beats, it pumps blood through a system of blood vessels, which carry blood to every part of the body. Blood pressure is the force that blood exerts on the walls of blood vessels. All or any of the events related to the flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next is called a cardiac cycle. Problems in the cardiac cycle can cause low or high blood pressure.
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The cardiac cycle involves- Ventricular diastole, venrricular systole and joint diastole. 1 cardiac cycle is of 0.8 seconds.

Diastole is the ventricular relaxation during which the semilunar valves close and blood is received by the ventricles from their respective atria. Venticular diastole lasts for 0.1 seconds.

Systole is the ventricular contraction during which the tricuspid valve closes and blood from the right ventricle enters the pulmonary artery while the bicuspid valve closes and blood from the left ventricle enters the systemic aorta. Ventricular systole lasts for 0.3 seconds.

Joint diastole is the relaxation of the ventricles and the auricles. During this time, the auricles receive blood from their respective blood vessels. Joint diastole lasts for 0.4 seconds.
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