Physiology 3120 Lecture Notes - Lecture 3: Molality, Aquaporin, Mucus
28 Dec 2017
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Document Summary
Movement of water down its concentration gradient due to its random thermal motion. Water concentration is determined by the number of solute particles in solution: not on the size of the solutes dissolved in water. High solute concentration = low water concentration. Low solute concentration = high water concentration. Requires a semi-permeable membrane which allows water across but not the solute: the cell membrane is selectively permeable. Water moves, not the solute, changing the volumes. Water moves into the area with a higher solute concentration. Osmotic pressure is measured in mmhg: pressure applied to the solution to stop osmosis, osmotic pressure depends on solute concentration (# of solute particle in solution) If there is no semi-permeable membrane, osmosis will not occur because there will be no concentration gradient. What would happen (roughly) to osmotic pressure if the concentration of nacl was doubled: osmotic pressure will double. Increase the driving force of water into the side with the high concentration.
