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Systole (/ ˈ s ɪ s t əl i / SIST-ə-lee) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. [1] Its contrasting phase is diastole , the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood.
During ventricular systole the ventricles contract and vigorously pulse (or eject) two separated blood supplies from the heart—one to the lungs and one to all other body organs and systems—while the two atria relax (atrial diastole). This precise coordination ensures that blood is efficiently collected and circulated throughout the body.
The first heart sound S1, is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as "lub". The second heart sound, S2, is the sound of the semilunar valves closing during ventricular diastole and is described as "dub". [1]
When the heart contracts during systole, the contraction compresses the coronary arteries, which prevents perfusion. Therefore, it is only when the heart relaxes, during diastole , that the coronary vessels open up and allow for perfusion; thus CPP is highest during diastole, unlike most other arteries, which experience higher perfusion ...
Severe ischemia can cause the heart muscle to die from hypoxia, such as during a myocardial infarction. Chronic moderate ischemia causes contraction of the heart to weaken, known as myocardial hibernation. [citation needed] In addition to metabolism, the coronary circulation possesses unique pharmacologic characteristics.
Heart sounds are the noises generated by the beating heart ... Normally A 2 precedes P 2 especially during inspiration where a split ... It is the loudest in systole ...
The average "normal" blood pressure is 120/80, according to the American Heart Association. Almost half of all U.S. adults have elevated blood pressure (systolic pressure between 120 and 19 and ...
In cardiac physiology, isometric contraction is an event occurring in early systole during which the ventricles contract with no corresponding volume change (isometrically). This short-lasting portion of the cardiac cycle takes place while all heart valves are closed.