How does the mammalian heart control blood flow to different parts of the body?
http://discoverysedge.mayo.edu/mechanisms/index.cfm
The mammalian heart controls blood flow to different parts of the body through a series of steps involving the coordination of its chambers, valves, and blood vessels.
To understand how this process works, let's break it down step by step:
1. The heart has four chambers: two atria (left and right) and two ventricles (left and right). Blood enters the heart through the atria and exits through the ventricles.
2. Deoxygenated blood, containing waste products and low levels of oxygen, enters the right atrium from the body through the superior and inferior vena cava.
3. From the right atrium, blood flows into the right ventricle. When the right ventricle contracts, it pumps the deoxygenated blood into the pulmonary artery.
4. The pulmonary artery carries the deoxygenated blood to the lungs, where it picks up oxygen and gets rid of waste products. This oxygenates the blood.
5. Oxygenated blood returns to the heart through the pulmonary veins and enters the left atrium.
6. From the left atrium, blood flows into the left ventricle. When the left ventricle contracts, it pumps the oxygenated blood into the aorta.
7. The aorta is the largest artery in the body and carries oxygenated blood to all parts of the body.
8. In order to regulate blood flow to different parts of the body, the heart has valves. These valves ensure a one-way flow of blood.
9. The tricuspid valve separates the right atrium from the right ventricle, preventing backflow of blood.
10. The pulmonary valve separates the right ventricle from the pulmonary artery, preventing backflow of blood.
11. The mitral (bicuspid) valve separates the left atrium from the left ventricle, preventing backflow of blood.
12. The aortic valve separates the left ventricle from the aorta, preventing backflow of blood.
By contracting and relaxing in a coordinated manner, the heart chambers and valves work together to control blood flow, allowing oxygenated blood to reach all parts of the body while efficiently removing waste products.