BIOA02H3 Lecture : Lecture for ch.51

• School: UTSC
• Department: Biological Sciences
• Course: BIOA02H3
• Professor: Mary Olaveson

Document Summary

Vertebrates are well adapted to excrete excess waste, nephron is the functional unit in kidney that excrete the wastes. Example: marine body fish, reptiles, birds and mammals, amphibians. Amphibians: (they spend long periods of time in water, estivation=state of low metabolic activity/low water demand, ectothermic (low temp-not very active), accumulate sugar to prevent them from freezing. Reptiles: have 3 major adaptations to exist outside of water: amniotic reproduction, shelled eggs, scaled epidermis that retards water loss, excretion of uric acid with little water loss. They try to maintain internal temperature to live. Have adapted to conserve water: amniotic reproduction, birds produce uric acid, both birds and mammals produce concentrated urine, surface coverings to reduce water loss. Humans produce more urine (about 4 times more) concentrated than blood. Mammalian excretory system: important feature is kidneys (site of water balance and salt regulation), kidneys are supplied with blood by a renal artery and renal vein.