Composed of upped right and left atria (similar, atrium) and lower right and left ventricles, the heart is a double pump. The atria contract and empty simultaneously into the ventricles, which contract in unison as well. The thin interatrial septum separates the atria. The thick muscular interventricular septum separates the ventricles. Positioned between the atria and ventricles are atrioventricular valves (AV valves), and potioned at the bases of the two large vessels leaving the heart are semilunar valves. Heart valves keep one-way flow of blood.
The following discussion follows the sequence in which blood flows through the atria, ventricles, and valves. It is important for us to remember that the right side of the heart (right atrium and right ventricle) receives deoxygenated blood (blood low in oxygen) and pumps it to the lungs. Oxygenated blood (blood high in oxygen) is received by the left side of the heart (left atrium and left ventricle) from the lungs and pumps it to the body.
Venous blood is received by the right atrium from the superior vena cava, which drains the upper portion of the body, and from the inferior vena cava, which drains the lower portion. The coronary sinus receives venous blood from the myocardium of the heart itself, and it is an additional opening into the right atrium.
- June 13, 2012 @ 02:26:16 [Current Revision] by Ji Guanghua
- June 13, 2012 @ 02:26:10 by Escritt
- April 3, 2011 @ 01:52:02 [Autosave] by Ji Guanghua
- April 3, 2011 @ 01:50:57 by Escritt
- March 30, 2011 @ 03:32:35 by Ji Guanghua
- March 30, 2011 @ 02:44:37 by Ji Guanghua
- March 30, 2011 @ 02:44:28 by Ji Guanghua