BIOL10004 Lecture 11: Module 3 Regulating-Body-Fluids-Homostasis
Document Summary
One of the most important body functions. If humans drink too much water (e. g. > 30 litres): water intoxication: kidneys can"t cope. Seizures, confusion, blurred vision, pain, cramps, death. 3min without o2, 3 hours without water, 3 days without food. Our internal environment may show how life started. Water diffuses through a semi-permeable membrane from an area of low osmotic concentration (low osmolarity/high water potential) to an area of high osmotic concentration (high osmolarity/low water potential) Osmolarity (solue concentration of solution of water/ osmotic concentration) = osmoles (osm/l) E. g. 1m solution of cacl2 has an osmolarity of 3. Solutes can move in or out of cells by active transport against concentration gradients (requires energy) Can be interchangeable with osmolarity, unable to cross a membrane. If it can"t cross a membrane it has a greater effect on osmosis- water movement. Like osmolarity, except takes into account only non- permeable solutes [see http://en. wikipedia. org/wiki/osmolarity] To achieve homeostasis constancy of the extracellular environment.
