Blood Vessels

Question 1

what is the function of arteries?

Answer 1

arteries carry blood away from the heart - the blood is flowing at high pressure

Question 2

what is the function of veins?

Answer 2

veins return blood into the heart - the blood is flowing at low pressure

Question 3

what are capillaries?

Answer 3

capillaries are tiny vessels and there are lots of them - they carry blood through all the tissues and are the site of exchange of materials by diffusion

Question 4

structure + function of an artery?

Answer 4

• thick outer wall - can transport blood at high pressure without bursting
• small lumen
• thick layer of elastic tissue - allows artery to stretch and recoil to keep blood flowing at high pressure
• thick layer of muscular tissue - helps to control flow of blood by widening and narrowing

Question 5

structure + function of a vein?

Answer 5

• fairly thin outer wall - blood is flowing at lower pressure so thick wall not needed
• thin layer of muscle and elastic tissue - wall can contract to keep blood flowing
• semilunar valves - prevents blood from flowing backwards

Question 6

structure + function of a capillary?

Answer 6

• wall is one cell thick - short distance for diffusion of substances from blood into tissues