Circulatory system - Blood vessels

Question 1

Arteries

Answer 1

Carry blood away from the heart

Question 2

Capillaries

Answer 2

Exchange nutrients + oxygen with body tissues

Question 3

Veins

Answer 3

Carry blood back to the heart

Question 4

Arteries (structure)

Answer 4

Blood inside arteries are at high pressures a they have just been pumped out of ventricles (need to be strong and elastic).
Therefore, they have a thick layer of both muscle and elastic tissue.
These layers are quite thick in comparison to the lumen (hollow area) within the blood vessel.

Question 5

Capillaries (structure)

Answer 5

Really small (therefore small lumen) and come into close contact with all cells in our body.
Role of exchanging substances within cells.

Walls of capillaries are a single-cell thick and are permeable, allowing substances to easily diffuse through them.
Arranged in large groups, therefore huge cross-sectional area –> lower blood pressure allowing more time for transfer of substances.

Question 6

Veins

Answer 6

Relatively large (have the largest lumens of all vessels) but have thin walls of elastic fibres and smooth muscle.
Carry low pressure blood.
Contain valves - prevent blood from flowing backwards.

Question 7

Calculating blood flow

Answer 7

amount of blood flowed / time = blood flow