Function

The cardiovascular system circulate blood throughout the body, bringing oxygen and nutrients to muscles and organs, and then returning with wastes in to the heart, cleaning takes place in lungs, to be pumped again. Any opposition in the flow of blood and the working heart can cause damage to an organ, including the heart. The system of channels through which the blood flows is called the circulatory system, and includes the heart, lungs, and blood vessels. Arteries, arterioles (small arteries), and capillaries (tiny blood vessels) carry blood from the heart to the body parts. Veins and venues (small veins) return the blood from the body parts to the heart.

The heart is a muscle about the size of a person's fist in the middle of the chest, tilted toward the left side. The heart beat is an expansion and contraction of the muscle as it pumps. Each day the heart beats about 100,000 times and pumps about 2,000 gallons of blood. It is made up of four chambers: two atria (right and left) and two ventricles (right and left). The atria are the upper chambers that receive the blood from body parts. The lower chambers, the ventricles, are thick-walled chambers made of muscle so they can pump the blood out of the heart. Four valves connecting the chambers, two valves in between artery and ventricle are bicuspid and tricuspid valves and major arteries help pump and carry the blood.