BIOL273 Lecture : CHAPTER 18 CHAPTER 18
16 Oct 2011
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Document Summary
Air movement from alveoli to cells: exchange of gases between two compartments diffusion across cell membranes, transport of gases in blood. Diffusion between alveoli and pulmonary capillaries fick"s law of diffusion: diffusion rate (surface area x * + gradient x membrane permeability)/membrane thickness. Surface area directly proportional: usually constant. [ ] gradient directly proportional: most important factor. Membrane thickness inversely proportional: usually constant. Diffusion distance faster over short distances: usually constant. Respiratory physiology [ ] gradient partial pressure to express gas concentrations: compare partial pressures of gases, establishes [ ] gradient between alveoli and blood. Dissolved gas depends on pressure, solubility, and temperature. Water in contact with gas pressure gradient: higher gas pressure in water gas molecules leave water, higher gas pressure in gas gas dissolves into water. Movement of gas molecules from air to liquid directly proportional to: pressure gradient of gas. 100 mmhg of oxygen in both liquid and gas. Does not mean [ ] is the same.
