Alveolar Gas Exchange + Gas Transport

Which gas is the most soluble in water

CO2

What does vapor pressure of water depend on

Temperature

What factors PROPORTIONATELY increase net rate diffusion of gas

Partial pressure between two ends; area; solubility of gas

What factors DISPROPORTIONATELY increase net rate diffusion of gas

Distance of diffusion and molecular weight of gas

What are the composition of air in atmosphere compared to alveoli

Atmosphere has higher pressure of O2, alveoli has higher CO2 and H2O

Why is slow gas exchange important

Prevents sudden change in gas concentration of blood → Becomes more stable

What layers make up the respiratory membrane

Layer of surfactant, alveolar EP, EP basement membrane, interstitial space, capillary basement membrane, capillary endothelial membrane

What diseases happen when the respiratory membrane is thicker than normal

Volume overload/heart failure (fluid in interstitial space), pulmonary firbrosis

What causes decreased surface area of the respiratory membrane

Emphysema → Dissolution of alveolar wall

How is diffusing capacity measured

PCO where the value is zero in blood → Find PCO diffusing capacity → Convert int PO2 diffusing capacity

What is shunt

Perfusion without ventilation (blood flows through lung but there is no gas exchange)

What is dead space

Ventilation without perfusion; air enters lungs but there is no blood flow for gas exchange 

Why is there always a V/Q mismatch

Pulmonary capillary blood flow and alveolar ventilation is less in upper lung

How is O2 diffuse into the pulmonary capillary from the alveoli

There is a pressure difference where capillary = 40 mmHg and alveoli = 104 mmHg

What determines tissue O2

Rate of O2 transport to tissue through blood; rate O2 is used by tissue

What causes a right shift in oxygen hemoglobin dissociation curve

Increase O2 release; increase H+, CO2, temp, BPG

What causes a left shift in oxygen hemoglobin dissociation curve

Decrease O2 release; decrease H+, CO2, temp and BPG

What is the haldane effect

Binding of O2 with Hb displaces CO2 and Hb becomes more acidic → Hb binds less to CO2 AND Hb release H+ to make HCO3-