The structure of a mammalian heart
- Created by: geburdon99
- Created on: 23-10-15 10:43
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- The structure of the mammalian heart
- The heart
- Muscular double pump.
- Divided into two sides.
- The right side pumps deoxygenated blood to the lungs for oxygenation.
- The left side pumps oxygenated blood to the rest of the body.
- On both sides, the heart squeezes the blood which puts it under pressure. This pressure forces the blood along the arteries.
- External features of the heart
- The ventricles are below the atria.
- The cornory arteries lie over the surface of the heart. They carry oxygenated blood to the heart itself.
- Restricted blood flow to the heart muscle reduces the delivery of oxygen and nutrients such as fatty acids.
- This can cause angina or myocardial infection.
- Restricted blood flow to the heart muscle reduces the delivery of oxygen and nutrients such as fatty acids.
- Internal features of the heart
- Deoxygenated blood flows the vena cava into the right atrium.
- Oxygenated blood from the lungs flows from the pulmonary vein into the left atrium.
- From the atria, blood flows down through the atrioventricular valves, into the ventricles.
- Inside the ventricles are tendinous cords.
- These attach the valves to the walls of the ventricle and prevent the valves from turning inside out which would allow blood to flow up the atria.
- Inside the ventricles are tendinous cords.
- Blood pressure
- Atria
- The muscle is thin. This is because these chambers do not need to create much pressure as the blood is only flowing into the ventricles.
- Right ventricle
- They have thick enough walls to ensure blood can be pumped out of the heart.
- The blood leaves this chamber to go to the lungs.
- Blood pressure cannot be too much as the capillaries in the lungs are very thin, and they are next to the alveoli, and they could burst.
- Left ventricle
- Their walls are two sometimes three times thicker than the right ventricle.
- The blood from the left ventricle is pumped out through the aorta and needs enough pressure to resist systematic circulation.
- Muscle of each chamber contracts to create increased pressure in the blood.
- Atria
- The heart
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