Diffusion

Question 0

What is the alveolar surface area?

Answer 0

Around 50-100 m2

Question 1

What is passive diffusion directly and inversely proportional to?

Answer 1

Directly: surface area
Inversely: thickness

Question 2

What is the thickness of a alveolar capillary wall?

Answer 2

1 um or less

Question 3

What is the main driving force of diffusion? Secondary forces?

Answer 3

1. Pressure differences
2. Molecular weight
3. Solubility

Question 4

Does CO2 or O2 dissolve better?

Answer 4

CO2 by 20x

Question 5

What gases are limited by diffusion in the lungs?

Answer 5

CO

O2

Question 6

What is the pressure of O2 in blood as it enters pulmonary capillaries?

Answer 6

40 mmHg O2

Question 7

What is the pressure of O2 in the alveolar space?

Answer 7

100 mmHg O2

Question 8

Under normal circumstances, how long does it take for O2 to diffuse across the alveolar capillary wall?

Answer 8

.25 seconds

Question 9

What is diffusion capacity?

Answer 9

Vco/(P1-P2)

Question 10

What is diffusion capacity usually equal to?

Answer 10

25 ml/min/mmHg

Question 11

What gases are limited by perfusion in the lungs?

Answer 11

N2O, CO2, O2