Alveolar-Capillary Diffusion

Question 1

What is Boyle’s Law?

Answer 1

P1V1=P2V2

Question 2

What is the definition of gas diffusion?

Answer 2

Net movement of the molecules of a gas from a region of higher concentration to a region of lower concentration

Question 3

How does the velocity of air flow change moving down the tracheobronchial tree?

Answer 3

It gets slower in smaller airways

Question 4

What is perfusion limited diffusion?

Answer 4

Diffusion of a gas where arterial concentration equilibrates with alveolar concentration in less time than the red blood cell spends in capillary circulation

Question 5

How is the diffusion of oxygen limited?

Answer 5

Perfusion limited

Question 6

What factors affect diffusion limited diffusion?

Answer 6

Diffusion characteristics of the barrier

Question 7

What is the diffusivity of carbon dioxide relative to oxygen?

Answer 7

CO2 has 20x greater than oxygen

Question 8

How can the diffusing capacity for a certain gas be calculated?

Answer 8

equal to uptake of that gas over the alveolar pressure of that gas minus the end capillary pressure

Question 9

What three physical factors have to be taken into account when thinking about the diffusion of a gas into the blood?

Answer 9

Diffusion through the alveoli, diffusion through the red blood cell membrane, and how much Hb is in the pulmonary capillaries

Question 10

What is the relative diffusing capacity for someone with anemia?

Answer 10

Low

Question 11

What are the four ways pathologies decrease the diffusing capacity?

Answer 11

Thickening of the barrier, decreased surface area, decreased uptake by erythrocytes, or ventilation-perfusion mismatch