ANSC 3080 Lecture Notes - Lecture 20: Hypoventilation, Hyperventilation, Vasoconstriction
27 Mar 2018
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Document Summary
Gas molecules constantly moving (collide) = exert pressure on the container. Total pressure: determined by the total number of gas molecule per volume unit. Partial pressure of gases: in a mixture = total pressure x % of that gas. Independent of other gases present in the mixture. Gas exchange depends on the delta p of specific molecules. Total pressure (sea level) = 760 mmhg. Partial pressure of o2 (po2) = 0. 21x760 = 159 mmhg. But air in the lungs is not dry. Inspired air is 100% saturated with water when it reaches the respiratory zone. Some of the air molecules colliding with water dissolve in water (don"t have to worry too much about this concept) Increase moisture in air will drive some gas molecules to be dissolved in water and this can impact the partial p. At equilibrium the relative amount of dissolved gas is constant. Depends of the solubility of the gas. At 37c, water vapour pressure is 47mmhg.
