by Megan Worley

Created on: March 04, 2009

The Structure and Function of the Human Heart

The heart, an organ about the size of a first operated as two coordinated pumps that send blood throughout the body. The heart is located in the upper chest just slightly left of center between the lungs.

The Structure of the Heart

The heart is divided into two sections by the interventricular septum, or simply the septum. Within each side of the heart it is also divided into two sections, upper and lower compartments. There are four main chambers, two on each side, including the right atrium and right ventricle and the left atrium and left ventricle.

The Superior vena cava is a large vein that carries deoxygenated blood into the right atrium from the head and upper body. Blood also enter the right atrium through the Inferior vena cava, another large vein, from the lower body. From the right atrium blood flows down into the right ventricle, passing through the Tricuspid valve. The Tricuspid valve is the right atrioventricular valve with three cusps. From the right ventricle oxygen-depleted blood flows out, through the pulmonary valve and into the pulmonary artery and into the lungs.

After traveling through the lungs and becoming re-oxygenated the blood travels back into the heart via the left and right pulmonary veins. From there blood flows into the left atrium, and then through the mitral valve and into the left ventricle. The mitral valve is the left atrioventricular valve which has two cusps. From the left ventricle the blood flows out through the Aortic valve into the Aorta. The Aorta is the biggest vein in the body and carries oxygenated blood to the rest of the body.

Function of the Heart

The heart serves the body by delivering oxygen to all of its cells through the blood that it pumps. The muscular wall of the heart, of the myocardium is constantly in action pumping blood and so like all other major organs in the body it needs a generous supply of blood and oxygen itself. This is supplied by coronary arteries.

The heart rate is controlled by the cardio regulatory center in the medulla of the brainstem. That area keeps the heart rate lower by sending electrical impulses along the nerves to keep the rate at about 70 beats per minute. Without that regulation the heart would beat at around 100 beats per minute. When the body is active or stressed these impulses are overridden by the hypothalamus to keep supplying the body with enough oxygen.

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