B2 : Blood Vessels

Question 1

What are the three main types of blood vessel

Answer 1

Arteries, veins, capillaries

Question 2

Arteries

Answer 2

Arteries carry blood AWAY from the heart to the organs or body, apart from the pulmonary artery the blood is oxygenated. Blood is under high pressure in the arteries. The arteries have a thick layer of muscle, elastic fibers and thick walls to withstand the high pressure. Arteries have a small lumen

Question 3

Veins

Answer 3

Veins carry blood towards the heart from the organs, the blood is deoxygenated (apart from the pulmonary vein). Veins have a larger lumen than arteries and have a relatively thin muscular and elastic walls because the blood is under less pressure. veins contain valves to prevent backflow of blood.

Question 4

Capillaries

Answer 4

Capillaries connect arteries to veins. Capillaries are narrow with thin walls ensuring short diffusion distance to surrounding cells. Helping glucose and oxygen easily diffuse out of blood into cells as well as allowing CO2 to do the opposite. Capillaries have narrow lumens which allow 1 cell to pass through at a time, the walls are 1 cell thick