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transport system[2]
Saturday, July 19, 2008
3:55 AM
In this post, the main focus will be on one of the main components of the circulatory system- the heart. Let's take a look on the anatomy of the human heart.

The heart sends blood around our body. The blood provides our body with the oxygen and nutrients it needs. It also carries away waste. Our heart is sort of like a pump, or two pumps in one. The right side of your heart receives blood from the body and pumps it to the lungs.





Heart Parts

The heart is made up of four different blood-filled areas, and each of these areas is called a chamber. There are two chambers on each side of the heart. One chamber is on the top and one chamber is on the bottom. The two chambers on top are called the atria. (singular: atrium) The atria are the chambers that are filled with blood returning to the heart from the body and lungs. The heart has a left atrium and a right atrium.

The two chambers on the bottom are called the ventricles. The heart has a left ventricle and a right ventricle. Their job is to squirt out blood to the body and lungs. Running down the middle of the heart is a thick wall of muscle called the septum. The septum's job is to separate the left side and the right side of the heart.

The atria and ventricles work as a team— the right atrium pumps the blood to the right ventricle, which then pumps the blood to the lungs via the pulmonary artery. After passing through the richly vascularized lung tissue, oxygen-rich blood return to the heart via the pulmonary vein and into the left atrium. The left atrium pumps the blood to the left ventricle, the launching pad that pumps the blood through the huge aortic artery and delivers blood to the rest of the body.

Well, our blood relies on four special valves inside the heart. A valve maintains the unidirectional flow of blood by opening and closing depending on the difference in pressure on each side. It keeps the flow of blood there by closing.

Two of the heart valves are the mitral valve and the tricuspid valve. They let blood flow from the atria to the ventricles. The other two are called the aortic valve and pulmonary valve, and they're in charge of controlling the flow as the blood leaves the heart. These valves all work to keep the blood flowing forward. They open up to let the blood move ahead, then they close quickly to keep the blood from flowing backward.


reference:
http://www.wanderings.net/
http://en.wikipedia.org/wiki/Heart_valve