Lecture 28

Question 1

What are the partial pressures?

Answer 1

Atmosphere: O2=160, CO2= 0.25
Lungs: O2=100, CO2=40
Cells: O2=40, CO2=46

Question 2

Describe Fick’s Law

Answer 2

rate of diffusion proportional to membrane permeability, concentration gradient, surface area
inversely proportional to diffusion distance ^2

Question 3

What determines the amount of O2 reaching the alveoli?

Answer 3

O2 content in the atmosphere (ex. altitude)
alveolar ventilation (lung compliance, airway resistance, CNS activity)
Fick’s Law
adequate perfusion (capillary reaching organ) of alveoli

Question 4

Describe emphysema

Answer 4

loss of elastin in the lungs, caused by destruction of the alveoli/SA

Question 5

Describe asthma

Answer 5

bronchioles constricted, lower PO2 gradient

Question 6

What causes fibrotic lung disease

Answer 6

Buildup of scar tissue around the alveoli leads to lack of compliance

Question 7

Describe a pulmonary edema

Answer 7

increased interstitial fluid, causes increased diffusion distance for gases