Ventricular systole

Ventricular systole is a stage in the cardiac cycle where the ventricles of the heart contract to pump blood to the body. This process is crucial for the proper functioning of the circulatory system and overall human physiology.

Overview

During ventricular systole, the ventricles contract following the receipt of an electrical signal from the sinoatrial node. This contraction causes an increase in pressure within the ventricles, leading to the closure of the atrioventricular valves and the opening of the semilunar valves. As a result, blood is pumped out of the ventricles and into the pulmonary artery and aorta.

Phases

Ventricular systole can be divided into two phases: the isovolumetric contraction phase and the ventricular ejection phase.

Isovolumetric Contraction Phase

In the isovolumetric contraction phase, the ventricles begin to contract with the atrioventricular valves already closed. The pressure within the ventricles increases but no blood is ejected as the pressure is not yet high enough to open the semilunar valves.

Ventricular Ejection Phase

During the ventricular ejection phase, the pressure within the ventricles exceeds the pressure in the aorta and pulmonary artery, causing the semilunar valves to open. Blood is then ejected from the ventricles and into the circulatory system.

Clinical Significance

Abnormalities in ventricular systole can lead to various cardiovascular diseases, including heart failure, myocardial infarction, and arrhythmias. Understanding the mechanics of ventricular systole is therefore crucial in the diagnosis and treatment of these conditions.

See Also

• Cardiac cycle
• Diastole
• Systole
• Heart

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