Anatomy
Chambers of the heart
Atria and Ventricles
The heart is a muscular pump that lies centrally within the chest. It's comprised of four separate chambers: two atria and two ventricles. The right side of the heart takes deoxygenated blood from the systemic circulation, and pumps it through the lungs to be oxygenated. The left side of the heart then receives the oxygenated blood, and pumps it back through the arterial system to supply the end organs.
Each of the cardiac chambers has its own defining features, depending on its function. The top two chambers are known as atria and are typically thin walled due to the low pressures that they endure. The ventricles are the two lower chambers. Of the ventricles, the left ventricle has the thickest muscular wall, as it is required to push blood all the way through the systemic circulation.
The four different chambers are highlighted below. Click on each one to find out more anatomical information.
Cardiac Valves
Heart valves prevent the back flow of blood through the cardiac system, maintaining normal unidirectional flow. They are situated in between the atria and the ventricles or in between the ventricles and major vessels.
The four valves of the heart, going from right side to left, are named:
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Tricuspid valve: separates the right atrium from the right ventricle and prevents back-flow into the right atrium during ventricular systole
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Pulmonary valve: prevents back-flow from the pulmonary artery into the right ventricle during diastole
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Bicuspid (mitral) valve: prevents back-flow from the left ventricle into the left atrium during systole
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Aortic Valve: prevents back-flow from the aorta into the left ventricle
