Osmoregulation and Excretion

Chapter 44

1. State the difference between an osmoregulator and an osmoconformer.

2. Describe the different osmoregulation challenges faced by freshwater and marine fishes.

3. Why do aquatic animals, mammals, and reptiles secrete nitrogenous wastes in different forms?

4. The key functions of excretory systems are filtration, reabsorption, secretion, and excretion. Describe each.

5. Describe the pathway of filtrate as it moves from blood to leaving the body.

6. Describe what happens to the filtrate as it moves through the

a) proximal tubule

b) descending limb of the loop of Henle

c) ascending limb of the loop of Henle

d) distal tubule

e) collecting duct

7. Why is water continuously lost as it moves through the descending limb of the loop of Henle?

8. Why is salt removed from the filtrate as it moves through the ascending limb of the loop of Henle?

9. The filtrate becomes less concentrated as it moves through the ascending limb of the loop of Henle even though no water is added to it. How can this be?

10. How is counter-current exchange an important aspect of the function of the kidney?

11. Describe the role of ADH in water balance.

12. Describe how the RAAS helps regulate water balance.

13. How does alcohol affect the regulation of water balance in the body?

14. How can eating salty food affect kidney function?