BIOL 1002 Lecture Notes - Lecture 15: Osmoregulation, Cryptobiosis, Osmotic Concentration
16 Aug 2019
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Document Summary
Physiological systems of animals operate in a fluid environment. Relative concentrations of water and solutes maintained within fairly narrow limits. Osmoregulation regulates solute concentrations and balances gain and loss of water. Freshwater animals show adaptions that reduce water uptake and conserve solutes. Desert and marine animals face desiccating environments that can quickly deplete body water. Excretion gets rid of nitrogenous metabolites and other waste products. Osmoregulation balances the uptake and loss of water and solutes. Osmoregulation based largely on controlled movement of solutes between internal fluids and external environment. Cells require a balance between uptake and loss of water. Osmolarity, solute concentrations of a solution, determines movement of water across spms. If two solutions isosmotic, movement of water is equal in both directions. If two solutions differ in osmolarity, net flow of water is from the hypoosmotic to the hyperosmotic solution. Osmoconformers (some marine animals) isosmotic with their surroundings and do not regulate their osmolarity.
