The left ventricle is the most heavily muscled and therefore, strongest of the chambers. The left ventricle pumps blood to the great aorta, which supplies the body with blood and oxygen. The chambers are separated from one another by muscle and a series of valves. The atrioventricular valve separates the right atrium and right ventricle, while the mitral valve separates the left atrium from the left ventricle. Each chamber and valve must function in a coordinated effort in order for the heart to pump efficiently.
Blood is composed of several different types of cells and proteins.
Red blood cells give blood its color and are responsible for the transportation of both oxygen and carbon dioxide to and from the body's tissues. Another constituent of blood is the infection-fighting white blood cells. A third cell type, the platelets, circulate in the blood and are responsible for clotting. Platelets, white blood cells and red blood cells are all formed within the bone marrow. In addition to cells, the blood is made up of a protein-rich liquid portion called plasma.