The body requires oxygen to carry on the process of life.
A network of arteries and veins transport oxygen-rich blood
to the body and carry oxygen-poor blood back to the lungs.
The heart pumps approximately 5 quarts of blood every minute,
and each heartbeat circulates blood to both the lungs and
the body. This is possible because of the heart's complex
internal structure.
Four valves keep the blood moving in the right direction.
Two of the heart valves separate the right and left atrium
from the right and left ventricles. Two other valves separate
the ventricles from the pulmonary artery and the aorta.
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The blood picks up oxygen in the lungs and then travels back
to the heart through the pulmonary veins. The pulmonary veins
empty into the left atrium, which contracts to push oxygen-rich
blood into the left ventricle. The left ventricle contracts,
pushing the blood through the aortic valve and into the aorta,
which connects to the rest of the body.
The heart is divided into the right side and the left side.
The right side, composed of the right atrium and ventricle,
collects and pumps oxygen-poor blood to the lungs to pick
up oxygen. The left side, composed of the left atrium and
ventricle, collects and pumps oxygen-rich blood to the body.
