BIOL 1070 Lecture Notes - Lecture 16: Glycolipid, Stoma, Thermoregulation
11 Mar 2016
School
Department
Course
Professor
Document Summary
Organisms must also balance the ion composiion of their intersiial luids. Ions are obtained from food or directly from the environment (especially in aquaic animals) Exchange occurs across cell membranes and the rate of exchange depends on the membrane surface area. A single celled organism has a large membrane surface area relaive to the volume of the cell. In mulicellular animals, not all cells are in contact with the environment and every cell must be in contact with the aqueous intersiial luid where dissolved substances can be exchanged. Complex animals must also have a circulatory luid that carries gases, wastes and nutrients to the intersiial luid. In addiion, respiratory and digesive systems have to have direct contact with the external environment. Animals maintain relaively constant internal condiions in the face of luctuaing external condiions. This is more profound in endotherms which must maintain a narrow range body temperature, as well as blood ph, ion concentraion, and glucose.
