Circulatory system

Question 1

Pericardium

Answer 1

• the fluid that surrounds the heart

Question 2

Artery

Answer 2

• thicker walls

Question 3

Veins

Answer 3

• large lumen

Question 4

Capillaries

Answer 4

• have thin one cell thick walls
• semi-permeable membrane
• this is to allow the diffusion of nutrients and minerals in the blood to the cells (e.g. oxygen)
• also to allow the diffusion of carbon dioxide from cells into the blood so that it can be excreted from the body through the lungs

Question 5

Artery vs Veins

Answer 5

• arteries have thicker walls to withstand the higher pressure in them, they have elastic fibres that allow constriction and dilation to control the flow of blood
• veins have thinner walls, no elastic fibres, have valves to stop the backflow of blood as it travels at a low pressure
• both have an tunica intima, tunic media, tunica extrena