Circulatory System

Question 1

Give two ways you can identify blood vessels

Answer 1

By the difference in lumen size

Difference in wall thickness

Question 2

Some people produce a much higher ventricular pressure than normal
This can cause tissue fluid build up outside the blood capillary of these people

Explain why

2 marks

Answer 2

1. More fluid forced / filtered out of capillary (due to high pressure)
2. Less return of fluid into capillary due to pressure
   Or
   Lymph system cannot drain away all excess fluid
   (Accept water for fluid)

Question 3

Explain the role of the heart in the formation of tissues fluid

2 marks

Answer 3

1. Contraction of ventricle produces high blood pressure/ hydrostatic pressure
2. This forces water / dissolved substances out of blood capillaries

Question 4

lymphoedema is a swelling in the legs which may be caused by a blockage in the lymphatic system

Suggest how a blockage in the lymphatic system could cause lymphoedema. 1 mark

Answer 4

Excess tissue fluid cannot be re absorbed / builds up (1)

Can say drained for reabsorbed

(Links to tissue fluid)

Question 5

Tick one box next to the blood vessel carrying blood at the lowest blood pressure.

1. Capillary
2. Pulmonary vein
3. Renal vein
4. Vena cava

Answer 5

4. Vena cava