Pulmonary Gas Exchange

Question 1

What is Dalton’s Law?

Answer 1

total pressure exerted by the mixture of nonreactive gases is equal to the sum of the partial pressures of individual gases.

Question 2

What is the equation of ideal gas law?

Answer 2

PV=nRT

Question 3

How is atmospheric air contents different from alveolar air contents?

Answer 3

Alveolar air has 6.18% water vapor.
6% less N in alveoli
1.3% less O2  in alveoli
.05% less Ar
CO2 is the same

Question 4

What is Boyle’s Law?

Answer 4

For a fixed amount of an ideal gas kept at a fixed temperature, P (pressure) and V(volume) are inversely proportional

Question 5

What is Henry’s Law?

Answer 5

At a constant temperature, 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 in equilibrium with that liquid.

Question 6

What is vapor pressure?

Answer 6

partial pressure exerted to escape form the liquid phase to the gas phase

Question 7

What is the vapor pressure at normal body temperature?

Answer 7

47mmHg

Question 8

True or False. Vapor pressure is independent of temperature of the water?

Answer 8

False. Vapor pressure of water depends on the temperature of the water.
0degrees C —-> VP=5mmHg
37 degrees C —> VP= 47mmHg
100 degrees C —-> VP= 760mmHg

Question 9

What 5 factors affect rate of gas diffusion in a fluid?

Answer 9

• solubility of gas in the fluid
• cross-sectional are of the fluid
• distance through which the gas must diffuse
• molecular weight of gas
• temperature of fluid (remains reasonably constant)

Question 10

What is the equation for gas diffusion rate?

Answer 10

add picturefrom slide

Question 11

True or False. Alveolar air is replaced by each breath.

Answer 11

False.The volume of alveolar air replaced by new atmospheric air with each breath is only one seventh of the total, so multiple breaths are required to exchange most of the alveolar air.

Question 12

What two factors controls the oxygen concentration within the alveoli?

Answer 12

• rate of absorption of oxygen into the blood

- rate of new oxygen entry into the lungs (alveolar ventilation)

Question 13

What two factors control the concentration of CO2 in the alveoli?

Answer 13

• rate of CO2 excretion

- alveolar ventilation

Question 14

What effect does increased CO2 excretion rate have on alveolar CO2 partial pressure?

Answer 14

alveolar partial pressure of CO2 will increase.

Question 15

What effect does increased alveolar ventilation have on the partial pressure of CO2?

Answer 15

The partial pressure of CO2 decreases as alveolar ventilation increases.

Question 16

What are the components of atmospheric air?

Answer 16

nitrogen 78%
O2 21%
Argon 1%
CO2 .03%