Pulmonary Gas Exchange

Question 0

What does Henry’s law state?

Answer 0

Henry’s law states that the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas at equilibrium.

Question 1

At sea level, how is the partial pressure of a specific gas in air be determined

Answer 1

by multiplying the percent of the gas in the air mixture by 760 mm Hg.

Question 2

What does Dalton’s law state?

Answer 2

Dalton’s law states that the total pressure exerted by the mixture of non-reactive gasses is equal to the sum of the partial pressures of individual gasses.

Question 3

What is Boyle’s law

Answer 3

Boyle’s law states that for a fixed amount of an ideal gas kept at a fixed temperature, P (pressure) and V (volume) are inversely proportional.

Question 4

The addition of water vapor to the mixture of air in the alveoli causes what?

Answer 4

decreases the partial pressures of all the other gasses in the mixture.

Question 5

Alveolar pressure at the end of a normal quiet inspiration cycle is ?

Answer 5

0 mm Hg.

Question 6

Normally, Va/Q =

Answer 6

0.8: (pulmonary = 5 L/min; Ventilation ≈ 4 L/min).

Question 7

Va/Q = 0 when Va = 0 but …..

Answer 7

there is still perfusion; this is due to airway obstruction (i.e., mucus plug). The blood gas composition remains unchanged.

Question 8

Va/Q = ∞ when Q = 0 but ……

Answer 8

there is still ventilation (no gas exchange); this is due to vascular obstruction (i.e., pulmonary embolism). Alveolar gas composition remains unchanged because there is no blood contact. This creates a physiologic shunt.