Chapter 22

• The total pressure of a gas mixture is the sum of the partial pressures exerted by the individual gases in the mixture.
• The partial pressure of each gas is independent of the other gases present.
• In gas mixtures, the concentration and the partial pressure of any given gas are simply proportional to each other.
• The proportionality coefficient is the same for all gasses, at any given temperature, because it is a corollary of the universal gas law.
• When gases dissolve in aqueous solutions, they disappear into the solution.
• The partial pressure of a gas dissolved in an aqueous solution is equal to the partial pressure of the same gas in a gas phase with which the solution is at equilibrium.
• In an aqueous solution, the concentration and the partial pressure of any given dissolved gas are proportional.
• The absorption coefficient varies greatly from gas to gas, and depends on temperature and salinity.
• Gas solubility decreases with increasing temperature and also with increasing salinity.
• Gases always diffuse from regions of high partial pressure to regions of low partial pressure and at a rate that is proportional to the difference in partial pressure.
• A gas is at equilibrium in a system when its partial pressure is uniform throughout.
• Diffusion occurs much more readily through air than water.
• When gas molecules undergo chemical combination, they cease to contribute to the partial pressure of the gas in question and thus no longer affect the direction or rate of diffusion of the gas,
• Convective gas transport occurs when a gas mixture or an aqueous solution solution flows and gas molecules in the gas or liquid are carried from place to place by fluid flow.
• Convection and diffusion alternate in transporting oxygen from the atmosphere to the mitochondria in a person.
• Convective transport flow of inhaled air from the atmosphere to the depths of the lung.
• Diffusion across a gas-filled alveolar end sac then through the alveolar epithelium and the epithelium of a pulmonary blood capillary, and finally into a red blood cell.
• Oxygen combines with hemoglobin in red blood cells.
• Convective transport of oxygen by the circulation of the blood.
• Diffusion from an RBC in a systemic blood capillary to a mitochondrion in a muscle cell.
• Convection and diffusion alternate in transporting oxygen from the atmosphere to the mitochondria in a person.