Mass transport-blood vessels

Question 1

Function of arteries

Answer 1

-Carry oxygenated blood at high pressure from the heart to the tissues

Question 2

What is the general structure of blood vessels?

Answer 2

-Tough fibrous outer layer:
>to resist pressure changes
-Muscle layer:
>that can contract and so control flow if blood
-Elastic layer:
>that helps to maintain blood pressure by stretching and springing back (recoiling)
-Endothelium:
>smooth to reduce friction, allow diffusion (shorter diffusion pathway)
-Lumen:
>Central cavity of blood vessel where blood flows

Though, muscular, elastic, endo

Question 3

Function of capillaries, how does rate of blood flow help with this?

Answer 3

Function:
>links arterioles to veins
>To exchange metabolic materials such as O2, C02 and glucose between blood and cells in body ( for this a short diffusion pathway is needed)
-Flow of blood in capillaries comparatively slower to allow for exchange of materials

Question 4

Structure of arteriole related to its function?

Answer 4

-Muscle layer relatively thicker than in the arteries, contraction of this muscle layer allows constriction of arteriole lumen
>this controls its movement into the capillaries, that supply tissues with blood
-elastic layer relatively thinner than in arteries
>because blood pressure lower in arteriole than artery, as arteriole carries blood from the arteries

Question 5

State the relative pressure of the arteriole compared to the artery, and the overall function of the arteriole.

Answer 5

-lower
-carry from arteries to capilleries, controlling the flow of blood between the two.

Question 6

State the structure of the arteries in relation to its function
(4)

Answer 6

-Muscle layer is thick compared to veins
>so smaller arteries can be constricted and dilated to control flow of blood passing through them
-Elastic layer is relatively thicker compared to veins, >helps maintain pressure of blood if it is to reach extremities of body
>helps maintains mooth pressure surges by stretching at systole, and recoiling and dyastol
-Overall thickness of the wall is great
>helps resist vessel bursting under pressure
-There are no valves
>as blood under constant high pressure due to being pumped by heart into arteries, so tends not to flow backwards

Question 7

What is different in the pulmonary arteries, compared to other arteries

Answer 7

-pulmonary arteries, which takes deoxygenated blood to the lungs ( unlike other arteries which take oxygenated from blood)
-pulmonary arteries have no valves

Question 8

state the structure of the veins in relation to its function (4)

Answer 8

-Muscle layer is relatively thin compared to arteries
>as veins carry blood away from the tissues so a high pressure is not needed to be maintained
-The elastic layer is relatively thin
>pressure in veins too low to cause them to burst, or to cause recoil action
-Overall thickness of wall is thin compared to arteries
>pressure not great enough to risk bursting
-Valves at intervals throughout
>ensure that blood does not flow backwards due to low pressure

Question 9

What is the function of the veins

Answer 9

-Veins transport blood slowly, at low pressure, from the capillaries in tissues to the heart

Question 10

state the structure of the capillaries in relation to its function (4)

Answer 10

-Walls one cell thick
>extremely thin walls = shorter diffusion pathway
-Numerous and highly branched
>provides large SA for exchange
-Narrow diameter
>so permeate cells, meaning no cell is far from a capillary = short diffusion pathway
-Spaces between endothelial cells
>allow white blood cells to escape and deal with infection

Question 11

What should be referenced in a question which asks you to describe how a blood vessels function is related to its structure

Answer 11

1) Structure
2) What this allows/means
3) How (2) relates to the function of the blood vessel

Question 12

what is a network of capilleries in a tissue called

Answer 12

capillery bed