(a)[4]
Explain how the structure of an artery is adapted for its function.
(b(i))[2]
Identify the cells present in the lumen of the arteriole in Fig. 4.1 and give one reason for your answer.
(b(ii))[4]
Describe the visible differences between the arteriole and the capillary in Fig. 4.1.
(c(i))[2]
Explain how tissue fluid forms in the capillary network.
(c(ii))[2]
The vessels labelled X in Fig. 4.2 return excess tissue fluid to the circulatory system. Name the fluid found in the vessels labelled X and state one way in which its composition differs from blood plasma.