Blood Vessels and Their Functions

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  • Created by: LucySPG
  • Created on: 27-05-13 16:39
What path does blood take to circulate the body?
Heart --> Aorta arteries --> Arterioles --> Capillaries --> Venules --> Veins --> Heart
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What is a blood vessel?
A tube with a space in the centre called the lumen where blood flows
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How many types of blood vessels do mammals have?
4
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What are the 4 types of blood vessels?
Arteries, arterioles, capillaries and veins
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What is the function of an artery?
Carries blood away from the heart into the arterioles
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What is the function of an arteriole?
Smaller artery that controls blood flow from artery to capillary
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What is the function of a capillary?
Tiny vessel that links arterioles to veins
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What is the function of a vein?
Carry blood from capillaries back to the heart
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What is the purpose of these different blood vessels?
To deliver blood to the capillary beds where substances are exchanged between cells and blood
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How many layers do arteries, arterioles and veins have?
5
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Name the 5 layers
Tough outer layer, muscle layer, elastic layer, thin inner lining - endothelium, and the lumen
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What does the tough outer lining do?
Resists pressure changes from both within and outside
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What does the muscle layer do?
Can contract and so control the flow of blood
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What does the elastic layer do?
Helps maintain blood pressure by stretching and springing back
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What does the endothelium do?
It is smooth to prevent friction and thin to allow diffusion
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What does the lumen do?
The lumen is not an actual layer but the central cavity of the blood vessel through which the blood flows
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What differs between each type of blood vessel?
The relative proportion of each layer
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Describe the muscle layer of the artery
Thick and muscular to withstand high pressures.
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Describe the elastic layer of the artery
Thick so that blood pressure is kept high. The stretching and recoil action helps to maintain this high pressure.
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Describe the lumen of the artery
Very narrow
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Describe the muscle wall of an arteriole
Thick. The contraction of this layer allows constriction of the lumen of the arteriole. This restricts the flow of blood and so controls its movement into the capillaries.
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Describe the elastic layer of an arteriole
Relatively thinner because blood pressure is lower
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Describe the muscular wall of a vein
Relatively thin compared to arteries because veins carry blood away from tissues and therefore their constriction and dilation cannot control the flow of blood to the tissues
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Describe the elastic layer of a vein
Relatively thin compared to arteries because the low pressure of the blood within the veins will not cause them to burst and pressure is too low to create a recoil action
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Describe the lumen of a vein
Wide lumen to reduce resistance to flow
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Describe the thickness of the wall of a capillary
Thin as it consists only of the lining layer
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Describe the lumen of a capillary
Wide. Red blood cells are squeezed flat against the side of a capillary which brings them even closer to the cells to which they supply oxygen.
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Card 2

Front

What is a blood vessel?

Back

A tube with a space in the centre called the lumen where blood flows

Card 3

Front

How many types of blood vessels do mammals have?

Back

Preview of the front of card 3

Card 4

Front

What are the 4 types of blood vessels?

Back

Preview of the front of card 4

Card 5

Front

What is the function of an artery?

Back

Preview of the front of card 5
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