Cardiac valves

The four cardiac valves direct the flow of blood through the heart during the cardiac cycle.

Gross anatomy

The heart valves are located in the cardiac fibrous skeleton:

  • two are atrioventricular (AV) valves: the right-sided tricuspid valve (TV) and left-sided mitral (bicuspid) valve (MV)
    • open during diastole to direct blood flow from the atria to the ventricles
    • close during systole to prevent regurgitation back into the atria from the ventricles
    • are attached to papillary muscles via chordae tendineae
  • two are semilunar valves: the right-sided pulmonary valve (PV) and left-sided aortic valve (AV)
    • open during systole to direct blood flow from the contracting ventricles through the right ventricle and left ventricle outflow tracts to the pulmonary trunk and ascending aorta, respectively
    • close during diastole to prevent regurgitation back into the ventricles from the pulmonary trunk and ascending aorta
    • these valves do not have chordae tendineae or papillary muscles

It is best to list the four valves in order of the series that blood travels through the heart:

  • venous blood returning from the body drains into the right atrium via the SVC, IVC and coronary sinus
  • the right atrium pumps blood through the tricuspid valve into the right ventricle
  • the right ventricle pumps blood through the pulmonary semilunar valve into the pulmonary trunk to be oxygenated in the lungs
  • blood returning from the lungs drains into the left atrium via the four pulmonary veins
  • the left atrium pumps blood through the bicuspid (mitral) valve into the left ventricle
  • the left ventricle pumps blood through the aortic semilunar valve into the ascending aorta to supply the body
  • See also

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