Coronary circulation
The heart itself needs to be supplied with blood. This is delivered by the two coronary arteries and their branches. The right coronary artery takes its origin from the aorta just distal to the aortic valve and appears on the surface of the heart between the pulmonary trunk and the auricle of the right atrium. Major branches of the right coronary artery include its marginal branch, posterior interventricular branch, and AV nodal branch. The right coronary artery is distributed to the right atrium, right ventricle, and variable portions of the left atrium and left ventricle.
The left coronary artery also arises from the base or ascending portion of the aorta. It is at first located between the pulmonary trunk and auricle of the left atrium. Major branches of the left coronary artery include its anterior interventric-ular branch and its circumflex branch. Thus, the left coronary artery supplies both ventricles, the inter-ventricular septum and the left atrium.
Most of the blood supplied by the coronary arteries is returned to the right atrium by way of the coronary sinus. Tributaries of the coronary sinus include the great cardiac vein, middle cardiac vein, and small cardiac vein. As mentioned in the pages on the structure of the heart, numerous microscopic veins, the venae cordis minimae, open directly into the heart chambers.
Failure of the coronary circulation causes ischaemic heart disease.
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