external and internal respiration
gas exchange, movement of o2 and co2. o2 and co2 move by diffussion down their gradients
dalton's law of partial pressure
the total pressure of a gas mixture (air) is equal to the sum of the pressures of the individual gases. a gas will diffuse down its partial pressure gradient.
pressure due to one gas within a mixture
will diffuse from high po2 to low po2
will diffuse from high pc02 to low pco2
gas exchange between air in alveolus and blood in pulmonary capillaries. o2 moves into blood and co2 moves out of blood
gas exchange between blood in systemic capillaries and tissues. 02 leaves blood co2 into blood.
blood flow in pulmonary capillaries
pulmonary capillaries pick up 02 and dump co2. pulmonary capillaries are under chemical control
if po2 is high and pco2 is low
good ventilation. causes vasodilation of local pulmonary capillaries
if po2 is low and pco2 is high
poor ventilation. cause vasoconstriction of the local pulmonary capillaries.