Concepts:

1. Composition of different body fluids is important for the function of the entire organism.
2. Animals can be grouped into osmoconformers and osmoregulators.
3. Obligatory and controlled osmotic exchange are the two forms involved in salt and water balance in animals.

Study Questions:

1. Which type of fluid compartments or fluids can be distinguished in animals?
2. What are the five most important/abundant ions in animals?
3. Which types of osmotic regulations are generally known?
4. Explain the term osmotic pressure.
5. Characerize changes of salt concentriations in an osmoregulator and osmoconformer.
6. What is the difference between a strict osmoregulator and an osmoregulator?
7. Which types of active and passive transport are known?
8. What type of proteins are involved in the transport of ions?
9. Compare the types of osmoregulation in Mytulis (mussel), Carcinus (Green Crab) and Procambarus (shrimp).
10. Describe the correlation between salt concentration and water transport in tissues.
11. What is the average osmolarity of seawater, freshwater, and blood of humans?
12. What are the concentrations of Na-, K-, and Cl-ions in freshwater and seawater?
13. Why is a marine fish with a blood osmolarity of 450 mosm an osmoregulator and not an osmoconformer?
14. If the osmolarities of seawater and hemolymph of a marine invertebrate were very similar, would you identify the invertebrate as an osmoconformer or osmoregulator? Why?
15. Freshwater and marine fish have similar serum osmolarities. How is this possible?
16. What is the function of organic ions in the regulation of salt and water balance?