This chamber is the heart's major pump, responsible for pumping the oxygenated blood through the aortic valve into the aorta and, eventually, to all parts of the body through a vast network of arteries, arterioles, and capillaries before it returns via the venules and veins a total of about 60,000 miles of blood vessels. In a normal, healthy adult, each ventricle pumps about 3 ounces of blood per beat, which adds up to about 2,100 gallons per day. Normal cardiac rhythm is maintained by the heart's electrical system, centered primarily in the group of specialized pacemaker cells in the sinus node. A system of valves keeps the blood moving in the right direction through the heart. The aorta forms the main trunk of the arterial system, arching over the heart and then branching to form the abdominal aorta, which carries blood to the abdomen.
Smaller arteries branching from the aorta carry blood to all parts of the body.
The arteries branch into smaller vessels called arterioles, which conduct blood from the arteries to the capillaries, the smallest blood vessels that carry oxygen and nutrients to the individual body cells and collect waste products to transmit to the venous system for the return journey to the heart and lungs.