BIOL 1082 Lecture Notes - Lecture 22: Purine, Coelom, Gout
Document Summary
Osmotic regulation i (reading: concepts: 44. 1-44. 3 in textbook: distinguish among the approaches used by osmoconformers and osmoregulators, listing examples of each. Stenohaline: most animals cannot tolerate substantial changes in external osmolarity and are said to be stenohaline. Euryhaline: euryhaline animals can survive large fluctuations in external osmolarity. Osmoconformers are isoomotic with their surroundings: all are marine animals, many live in water that has a stable composition and hence have a constant internal osmolarity, ex: (euryhaline) barnacles and mussels. The body fluids of freshwater animals must be hyperosmotic because animal cells cannot tolerate salt concentrations as low as that of lake or river water. Having internal fluids with an osmolarity higher than that of their surroundings, freshwater animals face the problem of gaining water by osmosis and losing salts by diffusion. This problem is solved by drinking almost no water and excreting large amounts of dilute urine.
