Blood Vessels 2 Flashcards Preview

B3 > Blood Vessels 2 > Flashcards

Flashcards in Blood Vessels 2 Deck (19)
Loading flashcards...
1
Q

What is the purpose of arterioles?

A
  • Carry blood under lower pressure than arteries
  • From arteries to capillaries
  • Control the flow of blood between the two
2
Q

How is the structure of arterioles related to function?

A

• Muscle layer is relatively thicker than in arteries
- Contraction of this muscle layer allows constriction of the lumen of the arteriole, restricts flow of blood and so controls its movement into the capillaries that supply the tissues with blood
• Elastic layer is relatively thinner than in arteries
- Because blood pressure is lower

3
Q

What is the purpose of veins?

A

Transport blood slowly under low pressure from the capillaries in tissues to the heart

4
Q

How is the structure of veins related to their function?

A
  • Muscle layer is relatively thin
  • Elastic layer is relatively thin
  • Overall thickness of the wall is small
  • There are no valves at intervals throughout
5
Q

Why do arteries have a thin muscle layer?

A

Compared to arteries, they have a thin muscle layer because:
• Veins carry blood away from tissues, and therefore their constriction and dilation cannot control the flow of blood of tissues

6
Q

Why is the elastic layer thin in arteries?

A

Thin compared to arteries because:
• Low pressure of blood within the veins will not cause them to burst
• Pressure is too low to create a recoil action

7
Q

Why is the overall thickness of the wall small in arteries?

A

This is because:
• There is no need for a thick wall as pressure within the veins is too low to create any risk of bursting
• Allows them to be flattened easily, aiding the flow of blood within them

8
Q

Why are there valves in the veins?

A
  • To ensure that blood does not flow backwards
  • Blood may flow backwards because the pressure is very low
  • When body muscles contract veins are compressed, pressurising the blood within them
  • Valves ensure that this pressure directs blood in one direction only: the heart
9
Q

What is the purpose of the capillaries?

A

To exchange metabolic materials such as oxygen, carbon dioxide and glucose between the blood and cells of the body.

10
Q

Why is the flow of blood in capillaries much slower?

A

To allow more time for exchange of materials

11
Q

How does the structure of capillaries relate to its function?

A
  • Walls consist mostly of the lining layer
  • Numerous and highly branched
  • Narrow diameter
  • Lumen is so narrow
  • Spaces between the lining cells
12
Q

How does a wall consisting of mostly of the lining layer relate to its function?

A
  • Makes capillaries extremely thin
  • The distance over which diffusion takes place is short, allowing for rapid diffusion of materials between the blood and cells
13
Q

How does having a narrow diameter relate to the function of the capillaries?

A

narrow diameter can permeate tissues which means that no cell is far from a capillary and there is a short diffusion pathway

14
Q

How does being numerous and highly branched relate to the function of capillaries?

A

Provides a large surface area for exchange

15
Q

How do spaces between the lining relate to the function of capillaries?

A

Allow white blood cells to escape in order to deal with infections within tissues

16
Q

Why is tissue fluid necessary?

A
  • Capillaries are small, they cannot serve every single cell directly
  • Final journey of metabolic materials is made to a liquid solution that bathes the tissues, this is tissue fluid
17
Q

What is tissue fluid?

A

Tissue fluid is a watery liquid that contains glucose, amino acids, ions in solution and oxygen.

18
Q

What is the purpose of tissue fluid?

A

• Supplies all of the substances to the tissues.
• Receives carbon dioxide and other waste materials from the tissues.
Means by which materials are exchanged between blood and cells, and it bathes all the cells of the body.

19
Q

Where is tissue fluid present?

A

• Immediate environment of cells