Excretion and Osmoregulation Questions
1. Which region of the kidney contains the Malpighian bodies, and which region the
loop of Henle and the collecting ducts?
2. Urine is carried first to the bladder thence onwards to the exterior of the body.
What is the name of the tube in each case?
3. Most nephrons of the human kidney are cortical
a. What is a juxtamedullary nephron?
b. Under which environmental conditions are animals most likely to have
evolved juxtamedullary nephrons?
4. Where does ultrfiltration occur in the vertebrate nephron? What is the source of
energy for ultrafiltration?
5. Which components of the body are normally never found in the filtrate of the
renal capsule?
6. List the main components of the blood which are likely to be filtered in the
nephron. Which of these are likely to be re-absorbed in the renal tube? What are
the energy sources for these two processes?
7. The cells of the proximal convoluted tubule have brush borders. What dos this
mean and what advantage does it confer?
8. List, in order the pathway blood takes as it passes through the kidney.
9. What is the effect of ADH on the permeability of the walls of the collecting
ducts? In what circumstance in the body is ADH released?
10. Why is an anticoagulant needed in the process of withdrawing blood fr dialysis?
11. How is it possible for the dialysate to be used to withdraw excess water from the
blood?
12. What advantage arises from arranging for blood and dialysate to flow in opposite
directions in the kidney machine?
13. In what form do fresh water fish get rid of their waste. Explain why it is possible
for them to excrete nitrogenous waste in this form.
14. Marine bony fish tissue fluid is hypotonic to the sea water, what will this cause to
happen and how does the fish get around the problem?
15. Cartilaginous marine fish store urea in their blood in order to keep their tissue
fluid isotonic to the surrounding water. What does this mean? Why is it not
possible for humans to do this?