Blood vessels and thier functions
- Created by: Beth Brown
- Created on: 17-05-11 11:21
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Four different types of blood vessels:
- Arteries - Carry blood away from heart and into the arterioles
- Arterioles - Smaller arteries that control blood flow from arteries to capillaries
- Capillaries - Tiny vessels that link arterioles to veins
- Veins - Carry blood from the capillaries back to the heart
Arteries,arterioles and veins have the same basic structure. From the outside in they have:
- Tough outer layer = resists pressure changes
- Muscle layer = contracts and relaxes to control flow of blood
- Elastic layer = Helps to maintain blood pressure by streching and pinging back
- Thin inner lining (endotherlium) = Smooth so prevents friction and thin to allow diffusion
- Lumen = Central cavity of the blood vessel through which the blood flows
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Arteries - strcuture and function
TRANSPORT BLOOD RAPIDLY UNDER HIGH PRESSURE FROM HEART TO TISSUES
- Thick muscle layer compared to veins = smaller arteries can constrict and dialate to control the volume of blood passing through
- Elastic layer is thin comapred to veins = Becuase blood pressure in the arteries needs to be kept high to reach everywhere in the body
- Thick wall = Makes sure the vessel doesn't burst under pressure
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