Biology 9700 · AS & A Level · Homeostasis in mammals
Homeostasis in mammals — practice question
Mammalian blood must keep its water potential within a tight range if cells are to work efficiently; this control is known as osmoregulation. Relative medullary thickness (RMT) shows how much of a kidney is made up of medullary tissue. $\text{RMT} = \dfrac{\text{thickness of medulla}}{\text{kidney size}} \times 10$. Table 1.1 gives the link between the RMT and the urine concentration formed by four mammals from different habitats.
(a(i))[2]
Name the nephron sections found in the medulla.
(a(ii))[1]
Name a hormone that helps in osmoregulation.
(a(iii))[4]
Describe how the RMT is related to urine concentration and explain why the beaver and the kangaroo rat show different data.
(b)[2]
Suggest how a warthog can survive for several months without drinking water.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “the loop of Henle” …