Paper 2 Heart

Question 1

L
O
R
D

Answer 1

Left
Oxygenated
Right
Deoxygenated

Question 2

Describe the flow of blood through the heart

Answer 2

Deoxygenated blood from the body comes into the right atrium of the heart through the vena cava. It moves down through the right ventricle and up through the pulmonary artery to the lungs. Oxygenated blood comes back to the heart through the pulmonary vein and into the left atrium, down through the left ventricle and pumped out of the heart and around the body through the aorta.

Question 3

Role of arteries

Answer 3

Carry the blood away from the heart

Question 4

Structure of arteries and why

Answer 4

• arteries carry blood under high pressure so the artery walls are strong and elastic
• walls are thick compared to the lumen (hole down the middle)
• contain thick layers of muscle to make them strong and elastic to allow them to stretch and spring back

Question 5

Role of capillaries

Answer 5

Involved in the exchange of materials at the tissues eg allowing blood to be oxygenated at the alveoli in the lungs

Question 6

Structure of capillaries and why

Answer 6

• arteries branch into capillaries
• they are very narrow and small so they can squeeze through into the gaps between cells meaning they can carry the blood really close to every cell in the body to exchange substances with them
• they have permeable walls so substances diffuse in and out
• they supply food and oxygen and take away waste like carbon dioxide
• their walls are usually one cell thick increasing the rate of diffusion by decreasing the distance over which it occurs

Question 7

Role of veins

Answer 7

Carry blood to the heart

Question 8

Structure of veins and why

Answer 8

• veins take blood back to the heart at low pressure so the walls don’t need to be thick, large lumen
• many veins contain valves which stop blood flowing backwards