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Heart

The hollow, muscular organ that maintains the circulation of the blood. NIH - National Library of Medicine

Illustration of the location of the heart in the body. Also shows the coronary arteries and major blood vessels. Click to enlarge

The heart in the chest and outside view of the heart National Institutes of Health

Illustration of a cross-section of a healthy human heart, including the heart valves. Click to enlarge

The inside of the heart, showing blood flow: red for oxygen-rich blood and blue for oxygen-poor blood National Institutes of Health

How the Heart Works

Your heart is a muscular organ that pumps blood to your body. Your heart is at the center of your circulatory system. This system consists of a network of blood vessels, such as arteries, veins, and capillaries. These blood vessels carry blood to and from all areas of your body.

An electrical system controls your heart and uses electrical signals to contract the heart's walls. When the walls contract, blood is pumped into your circulatory system. Inlet and outlet valves in your heart chambers ensure that blood flows in the right direction.

Your heart is vital to your health and nearly everything that goes on in your body. Without the heart's pumping action, blood can't move throughout your body.

Your blood carries the oxygen and nutrients that your organs need to work well. Blood also carries carbon dioxide (a waste product) to your lungs so you can breathe it out.

A healthy heart supplies... Read more about the Heart

Terms to know

Aorta
The largest artery in the body. It carries oxygen-rich blood away from the heart to vessels that reach the rest of the body.
Aortic Valve
A valve that is located between and controls the flow of blood from the left ventricle of the heart and the aorta.
Atria
The chambers of the heart, to which the blood returns from the circulation.
Cardiac Valves (Heart Valves)
Any of the four heart valves that regulate the flow of blood through the chambers of the heart.
Coronary Artery
A principal artery that originates in the aorta. It supplies blood to the muscular tissue of the heart.
Heart Ventricles
The lower right and left chambers of the heart.
Inferior Vena Cava
A large vein that empties into the heart. It carries blood from the legs and feet and from organs in the abdomen and pelvis.
Interventricular Septum
Interventricular septum is the stout wall separating the lower chambers (the ventricles) of the heart from one another.
Mitral Valve
Valve between the left atrium and left ventricle of the heart.
Pulmonary Artery
The pulmonary artery and its branches deliver blood rich in carbon dioxide (and lacking in oxygen) to the capillaries that surround the air sacs.
Pulmonary Valve
A valve that is located between, and controls the flow of blood from, the right ventricle of the heart and the pulmonary artery.
Pulmonary Veins
The veins that return the oxygenated blood from the lungs to the left atrium of the heart.
Superior Vena Cava
The large vein that carries blood from the head, neck, arms, and chest to the heart.
Tricuspid Valve
The valve consisting of three cusps situated between the right atrium and right ventricle of the heart.

Terms to know

Aorta
The largest artery in the body. It carries oxygen-rich blood away from the heart to vessels that reach the re...
Aortic Valve
A valve that is located between and controls the flow of blood from the left ventricle of the heart and the a...
Atria
The chambers of the heart, to which the blood returns from the circulation....
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