Gas Exchange and Transport: Oxygen

Define partial pressure of gas and what does gas exchange depend on

• the pressure exerted by an individual gas within a mixture of gases

• gas exchange depends on differences in partial pressures between areas

List the law associated with partial pressure of gas, list the equation and define each variable

• Dalton’s Law

• Pgas = Patm x Fgas

  • Pgas = partial pressure of the gas

  • Patm = atmostpheric pressure

  • Fgas = fractional concentration of gas

List factors affecting partial pressure

• Atmospheric pressure

• Fractional concentration of gas

• Water vapor

• Carbon dioxide

Define oxygen affinity

oxygen affinity describes how strongly hemoglobin binds oxygen

Define high and low oxygen affinity

• High affinity → hemoglobin binds O2 strongly

• Low affinity → hemoglobin releases O2 more easily

Define P50 and list what happens to affinity when there is a low or high P50

• partial pressure of oxygen at which hemoglobin is 50% saturated

• Low P50 = high affinity

• High P50 = low affinity