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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.
The section shows: 1) the opened ventricles contracting once per heartbeat—that is, once per each cardiac cycle; 2) the (partly obscured) mitral valve of the left heart; 3) the tricuspid and pulmonary valves of the right heart—note these paired valves open and close oppositely. + (The aortic valve of the left heart is located below the ...
A Wiggers diagram, named after its developer, Carl Wiggers, is a unique diagram that has been used in teaching cardiac physiology for more than a century. [1] [2] In the Wiggers diagram, the X-axis is used to plot time subdivided into the cardiac phases, while the Y-axis typically contains the following on a single grid: Blood pressure. Aortic ...
The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle. The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole.
Cardiac output (= heart rate * stroke volume. Can also be calculated with Fick principle, palpating method.) Stroke volume (= end-diastolic volume − end-systolic volume) Ejection fraction (= stroke volume / end-diastolic volume) Cardiac output is mathematically ` to systole [clarification needed] Inotropic, chronotropic, and dromotropic states
Wiggers diagram of the cardiac cycle, with isometric contraction marked at upper left. 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
After nourishing the heart muscle, blood returns through the coronary veins into the coronary sinus and from this one into the right atrium. Backflow of blood through its opening during atrial systole is prevented by the Thebesian valve. The smallest cardiac veins drain directly into the heart chambers. [10]
This condition occurs when heart muscle is gradually infiltrated or replaced by scar tissue or when abnormal substances accumulate in the heart muscle. The ventricular systolic pressure remains normal, diastolic pressure is elevated and the cardiac output is reduced.