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Flashcards in normal lung alveolar gas exchange Deck (18):
1

partial pressure of gas in ambient air

- Pgas= Fgas x Patm
- Pgas = partial pressure of a gas
- Fgas = concentration of a gas (.21)
- Patm = atmospheric pressure (760mm Hg)

2

partial pressure of H2O vapor conducting zone (PH2O)

- 47 mm Hg

3

partial pressure of of gas in inspired air

- PIgas = Fgas (Patm - PH2O)

4

partial pressure of O2 in alveolus (PAO2)

- 100 mm Hg
- gas equation (Patm - 47)fO2- PCO2/R
(760-47).21-40/.8

5

partial pressure of CO2 in alveolus (PACO2)

- 40 mm Hg
- inverse to alveolar ventilation
- hyper and hypoventilation

6

partial pressure of O2 in arterial (PaO2)

- 100 mm Hg

7

partial pressure of CO in arterial (PaCO2)

- 40 mm Hg

8

partial pressure of O2 in alveolus (PAO2)
partial pressure of O2 in arterial (PaO2)

= equals to 100 mm Hg diffusion will take place
is at equilibrium
- SAME CONCEPT IN CO2 = 40 mm Hg

9

diffuse first out of the capillary O2 or CO2

- CO2 due to its high solubility even thou it has a smaller pressure gradient
- CO > CO2 > O2 pressure is constant and equal for all

10

PAO2 is proportional to Patm, fO2 and PaO2

- Patm
- fO2

11

respiratory zone

- alveoli are found
- PAO2 = (Patm - 47)fO2- PCO2/R
- IN THE ALVEOLUS

12

conducting zone

- PiO2 = (Patm - 47)fO2

13

diffusion capacity of the lung

- PERFUSION- LIMITED
- DIFFUSION- LIMITED

14

PERFUSION-LIMITED

- substance EQUILIBRATES between the capillary and interstitium

15

DIFFUSION-LIMITED

- substance DOES NOT equilibrate between capillary and interstitium

16

affinity to hemoglobin

- CO > O2 > CO2

17

SOLUBILITY

- CO > CO2 > O2

18

which of the ff gases is best indicated to measure the diffusing capacity of the lung (allow the gases to diffuse at is wall)

- CO
- carbon monoxide
- attach to hgb causing partial pressure to be ZERO