7.6- Blood vessels and their functions

  • Created by: Megan2413
  • Created on: 13-03-17 19:28
Name four types of blood vessel
- Arteries - Arterioles - Capillaries - Veins
1 of 28
What are arterioles and their function?
They are smaller arteries that control blood flow from arteries to capillaries
2 of 28
What five main components is there to a blood vessel?
- Tough fibrous outer layer - Muscle layer - Elastic layer - Thin inner lining - Lumen
3 of 28
What is the tough fibrous outer layer and its function?
It resists pressure changes from both within and outside
4 of 28
What is the muscle layer and its function?
It can contract and relax, hence control the flow of blood
5 of 28
What is the elastic layer and its function?
It helps to maintain blood pressure by stretching and recoiling
6 of 28
What is the thin inner layer and its function?
It is made up of endothelium cells that are smooth to reduce friction and thin to allow diffusion
7 of 28
What is the lumen and its function?
It is the central cavity of the blood vessel through which the blood flows
8 of 28
What three main differences are there between the structure of an artery and a vein?
- The lumen size - The thickness of the elastic layer - The thickness of the muscle layer
9 of 28
How are capillaries different in structure to arteries and veins?
They only consist of the thin inner layer and lumen
10 of 28
What four features make the artery structure related to its function?
- The muscle layer is thick compared to veins - The elastic layer is relatively thick compared to veins - The overall thickness of the wall is great - There are no valves
11 of 28
Why is the muscle layer in an artery thicker than in veins?
The smaller arteries can be constricted an dilated in order to control the volume of blood passing through
12 of 28
Why is the elastic layer realtively thicker in arteries than veins?
The blood pressure in arteries is higher and needs to be maintained high, the elastic walls allow the artery to strech and recoil to help maintain high pressure
13 of 28
Why is the overall thickness of artery walls greater than in veins?
It resists the artery from bursting under the high blood pressure
14 of 28
Why is there no need for valves in arteries?
Due to blood constantly being under high pressure there is not going to be any backflow of blood
15 of 28
What two features make the arteriole structure related to its function?
- The muscle layer is relatively thicker than in arteries - The elastic layer is relatively thinner than in arteries
16 of 28
Why is the muscle layer in arterioles thicker than in arteries?
The contraction of the muscle layer allows constriction of blood flow into the capillaries
17 of 28
Why is the elastic layer realtively thinner in arterioles than in arteries?
The blood pressure is lower, so they are less likely to burst
18 of 28
What four features of the vein make its structure related to its function?
- The muscle layer is relatively thin - The elastic layer is relatively thin - The overall wall thickness of the wall is small - There are valves at intervals throughout
19 of 28
Why is the muscle layer relatively thin in a vein?
Their constriction and dilation cannot therefore affect the flow of blood to the heart
20 of 28
Why is the elastic layer relatively thin too?
The blood in veins is at a low pressure so the elastic is not needed to stretch and recoil as much
21 of 28
Why is the overall thickness of vein walls thin?
There is no need for a thick wall due to low blood pressure- there is not risk of the walls bursting
22 of 28
Why are there valves throughout the venous system?
To ensure that blood doesn't flow backwards as the low pressure doesn't drive it forward
23 of 28
What four features of a capillary link its structure to its function?
- The walls consist mostly of the lining layer - They are numerous and highly branched - The lumen is narrow - There are spaces between the lining (endothelial) cells
24 of 28
Why do their walls mainly consist of the lining layer?
This makes them extremely thin hence a short diffusion pathway for exchange of substances
25 of 28
Why are they numerous and highly branched?
It increases surface area for diffusion
26 of 28
Why is their lumen diameter so small?
Red blood cells are squashed up against the walls as the lumen is so small which decreases diffusion pathway
27 of 28
What is the use of spaces between the endothelial cells in the lining?
It allows substances to reach every cell in the body for respiration as it is impossible for capillaries to reach every cell in the body
28 of 28

Other cards in this set

Card 2

Front

What are arterioles and their function?

Back

They are smaller arteries that control blood flow from arteries to capillaries

Card 3

Front

What five main components is there to a blood vessel?

Back

Preview of the front of card 3

Card 4

Front

What is the tough fibrous outer layer and its function?

Back

Preview of the front of card 4

Card 5

Front

What is the muscle layer and its function?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Mass transport resources »