Block 2b Gas Exchange

Question 1

What is the solubility coefficient for O2?

Answer 1

0.024

Question 2

What is the solubility coefficient for CO2?

Answer 2

0.57

Question 3

What is the solubility coefficient for CO?

Answer 3

0.018

Question 4

How does room air differ from alveolar air?

Answer 4

alveolar air is humidifed, so that room air gas concentrations are diluted by water vapor

Question 5

What is the function of FRC?

Answer 5

limiting of breath-to-breath fluctuation in gas exchange (blood O2, CO2, pH)

Question 6

What is the normal FRC?

Answer 6

2300 mL

Question 7

What is normal tidal volume?

Answer 7

350 mL

Question 8

By how much does alveolar ventilation usually increase in exercise?

Answer 8

4-fold

Question 9

What factors influence composition of alveolar gas?

Answer 9

ventilation, O2, CO2

Question 10

What structures make up the respiratory unit?

Answer 10

respiratory bronchiole, alveolar duct, atria, alveoli

Question 11

What is the average thickness of the respiratory membrane?

Answer 11

0.6 um with surface area of 70 m2

Question 12

What are the 6 layers of the respiratory membrane

Answer 12

1) surfactant 2) alveolar epithelium 3) alveolar basement membrane 4) interstitial space 5) capillary basement membrane 6) capillary endothelium

Question 13

What is the diameter of a capillary?

Answer 13

5 um

Question 14

What is the blood volume of the capillaries of the respiratory unit?

Answer 14

60 - 140mL

Question 15

What is the normal diffusion capacity of O2 at rest (exercise)?

Answer 15

21 mL/min/mmHg (65)

Question 16

Why can’t diffusion capacity of CO2 be measured?

Answer 16

diffuses too rapidly

Question 17

What molecular factors determine the diffusion coeffecient?

Answer 17

solubility & square root of molecular wieght

Question 18

What diffusion capacity factor is compromised in lung resection or emphysema?

Answer 18

surface area

Question 19

How is the Bohr equation used?

Answer 19

to determine physiological dead space