Gas Exchange and Transport Flashcards
atmospheric air is
a gaseous mixture of approximately 78% nitrogen, 21% oxygen, 0.4% carbon dioxide, and minute amounts of other gases
partial pressure of oxygen in atmospheric air (pO2)
is approx 160 mm Hg
partial pressure of carbon dioxide (pCO2)
is approximately 0.3 mm Hg
when air and water meet at the respiratory membrane
each gas diffuses along its concetration gradient until its partial pressure in air equals its partial pressure in water
pO2 is relatively higher in
relatively higher in alveolar air, blood “loads” oxygen in the lungs
pCO2 is relatively higher in
relatively higher in alveolar blood, it “unloads” carbon dioxide in lungs
pO2 approximately…
104 mm Hg alveolar air, while pO2 in the blood entering the capillaries is approx 40 mm Hg
oxygen will diffuse
along pressure gradient out of the alveoli and into the blood
pCO2 in the blood entering the capillaries is
approx 46 mm Hg while pCO2 in alveolar air is approx 40 mm Hg
carbon dioxide will diffuse
along a pressure gradient out of the blood and into the alveoli
the rate of alveolar gas exchange is effected
by various factors
like, difference in partial pressures of gases and solubility of the gases in respiratory fluids
at high altitudes
pO2 is low; pressure gradient is smaller and less oxygen diffuses into blood
under hyperbaric conditions
pO2 is very high; pressure gradient is great, more oxygen diffuses into blood
carbon dioxidle is the _______soluble of gases in blood plasma….
most soluble
oxygen is 5% soluble in blood plasma
nitrogen is 2.5% soluble
CO2 quickly diffuses even though it has smallest pressure gradient (henry’s law)
respiratory membrane is
relatively thin so gases diffuse across it without difficulty
