BIOL373 Lecture Notes - Lecture 5: Pressure Gradient, Alveolar Pressure, Venous Blood
11 Jan 2015
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Document Summary
Exchange of gases between compartments, which requires diffusion across cell membranes. Diffusion rate = (surface area x concentration gradient x membrane permeability) / membrane thickness. Most important factor usually is concentration gradient, other 3 rates are constant. Dissolved gas depends on pressure, solubility and temperature. Pressure gradient occurs when gas placed with water: if gas pressure higher in water, gas molecules will leave water, if gas pressure higher in gaseous phase, gas dissolves in water. Movement of gas molecules from air to liquid dependent on 3 things: pressure gradient of gas, solubility of gas in liquid, temperature. Solubility = the ease with which a gas dissolves in a liquid. If a gas very soluble, large numbers of gas molecules go into solution at low gas partial pressure. At equilibrium the movement of oxygen from air into water is equal to movement of oxygen from water to air. That does not mean the concentration oxygen is same in air and.
