BIOL 1503 Chapter : Internal Environment
Document Summary
Water balance & excretion: marine inverts isosmotic to environment=osmoconformeres, marine vertebrates & all freshwater & terrestrial inhabitants must osmoregulate, osmoregulators expend energy to control water uptake and loss. In a hyperosmotic or hypoosmotic environment: environment & evolution determines types of nitrogenous waste, most animals are stenohaline, cannot tolerate substantial changes in external osmolarity, euryhaline animals, can survive large fluctuations in external osmolarity, often live in estuaries. Osmoregulation in marine fish: marine teleosts=hypoosmotic to ocean, constantly losing h2o, drink constantly, scanty urine, fig 44. 3a, chart in review section. Freshwater fish osmoregulate: freshwater teleosts=hyperosmotic to lake/stream, constantly gaining h2o, avoids drinking, large amounts of water urine, fig 44. 3b. An animal"s nitrogenous wastes reflect it phylogent and habitat. Kidney functions: maintains homeostasis, regulates plasma levels using adh (antidiuretic hormone, regulates ion excretion, acid-base regulation: only place to excrete h, eliminates metabolic wastes: urea & creatine. Kidney anatomy: located retroperitoneally, know: cortex, medulla, pelvis, ureters, & urethra, fig 44. 10.
