BIO1022 Study Guide - Final Guide: Allantoin, Amniote, Osmoregulation
Document Summary
Balancing the uptake of water and solutes. Mammals also produce uric acid, but is usually converted to allantoin or excreted in urine. Do not need to cope with water movement. Tend to lose water and gain salt by osmosis due to ocean salinity. Gain water and salt from food and sea water. Osmotic water loss through gills and body surface. Excretion of excess ions and small amount of water in limited urine from kidneys. Tendency to gain water and lose salts. Water loss to the environment is a constant problem. Moist-skinned animals must avoid desiccation e. g. worms, snails, frogs. Reptiles have low skin and respiratory water loss- excrete urate to conserve water. Birds and mammals use water to keep cool. Often high evaporation from skin and respiratory surfaces. Cooling of air on exhalation saves water. Filtrate modified by secreting or reabsorbing water and ions. Passive and active transport used to concentrate filtrate. Water moves from interstitial fluid to lumen.
