The heart is a hollow muscular pump consisting mainly of myocardium, a type of muscle that can work without resting. The interior of the heart is divided into two halves, each of which consists of an upper chamber and a lower chamber (the atrium and the ventricle). Each chamber connects to one or more blood vessels. Blood flow through these chambers is controlled by one-way valves.
Function: Blood supply to the heart
The coronary arteries branch off the aorta and surround and penetrate heart muscle. Arterioles and capillaries branch off from the arteries to supply heart muscle with oxygen-rich blood. Deoxygenated blood drains into the coronary veins, which carry it back into the heart’s right atrium.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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