Blood vessels

Question 1

What are the three types of blood vessel?

Answer 1

1) Arteries- carry blood away from the heart.
2) Capillaries- exchange materials at the tissues.
3) Veins- Carry blood to the heart.

Question 2

Describe the arteries: (2)

Answer 2

1) The walls are strong and elastic to maintain the bloods high pressure, they are very thick compared to the hole down the middle (lumen).
2) They have thick layers of muscle to make them strong and elastic fibres to allow them to stretch.

Question 3

Describe the capillaries: (4)

Answer 3

1) Arteries branch into capillaries, they are too small to see.
2) They carry blood very close to each cell so they can exchange substances, because of this they have permeable walls which allow diffusion.
3) They supply food and oxygen and remove waste like C02.
4) Their walls are 1cell thick so the rate of diffusion increases as the distance decreases.

Question 4

Describe the vein: (3)

Answer 4

1) Capillaries join to form veins, the bp is low so the walls aren’t thick.
2) They have bigger lumen than arteries to help blood flow.
3) They have valves to help keep the blood flowing in the correct direction.

Question 5

How do you calculate the rate of blood flow?

Answer 5

rate of blood flow = volume of blood / number of minutes

e.g. 1464ml of blood passed through an artery in 4.5 minutes. Calculate the rate of blood flow through the artery in ml/min.
1464 / 4.5 = 325ml/m