08.12 - Gas Exchange, Oxygen Transport (Waters) - Questions Flashcards Preview

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Flashcards in 08.12 - Gas Exchange, Oxygen Transport (Waters) - Questions Deck (44):
1

Respiratory Quotient

Ratio of CO2 produced to O2 consumed

2

Respriatory Quotient depends on

what we eat and burn

3

Partial Pressure of inspired O2 vs dry air

159 vs 150

4

Henry's Law

Cx = (alpha)Px [partial pressure x solubility]

5

How do we measure diffusing capacity of lung

Single breath inhalation of carbon monoxide

6

Diffusion rate of CO2 vs O2 in blood and tissue

CO2 diffuses 20 times faster than O2

7

Solubility of CO2 vs O2

CO2 is about 23 times that of O2

8

Partial Pressure of O2 in arterial system

100 mmHg

9

Partial Pressure of O2 in venous system

40 mmHg

10

Partial Pressure of CO2 in arterial system

40 mmHg

11

Partial Pressure of CO2 in venous system

46 mmHg

12

Partial Pressure of O2 in Alveolus

105 mmHg

13

Partial Pressure of CO2 in Alveolus

40 mmHg

14

What determines Alveolar PCO2

CO2 production in body/ Alveolar ventilation

15

If CO2 production is constant, then PACO2 is determined by

Alveolar Ventilation

16

How does cellular O2 consumption affect PAO2

Decreases, more O2 will leave alveoli and enter blood

17

Alveolar Gas Equation

PAO2 = PIO2 - PACO2/R

18

Definition of Hypoxemia

Arterial PO2 < 100mmHg

19

A - a gradient is a measure of

whether O2 has equilibrated b/t alveolar gas and pulmonary capillary blood

20

A - a gradient is useful for

examining causes of hypoxemia

21

Ratio of arterial PO2 to fraction of inspired air is used as a measure of

Acute Lung Injury

22

What is used as a measure of Acute Lung Injury

Ratio of Arterial PO2 to Fraction of Inspired Oxygen

23

Gas transfer is said to be ____-limited

Perfusion-limited, b/c all blood leaving capillary ahs reached equilibrium with the alveolar gas

24

CO transfer is ____-limited

Diffusion limited

25

What causes oxidation of Iron to Methemoglobin

Nitrites and Sulfonamides

26

T/F: Oxygen bound to Hb does not contribute directly to the PO2 of the blood

TRUE

27

Typical percent saturation of Hb as it leaves most tissue capillaries

75%

28

4 Causes of Decreased Hb affinity for O2

PCO2 up, pH down, Temp up, 2,3-DPG up

29

4 Causes of Increased Hb affinity for O2

PCO2 down, pH up, Temp down, Fetal Hb up, 2,3-DPG down

30

What increases 2,3-DPG

Metabolite of glycolytic pathway, increased in hypoxia --> Decrease affinity for O2

31

How does CO affect O2 affinity

Increase, making more difficult to release

32

3 mechanisms for CO2 transport in blood:

(1) Dissolved CO2; (2) Protein carbamylation, Carbaminohemoglobin; (3) Formation of Bicarb

33

Amount of CO2 dissolved in blood is determined by

Henry's Law

34

How does CO2 bind to proteins in blood

binds to amine goups

35

Hamburger's Phenomenon

(1) Diffusion of HCO3- back into plasma causes decr. In net neg charge in cell; (2) Cl- moves into cell; (3) Cl- drags H20 into cell, causing swelling

36

What causes Cl- shift in Hamburger's Phenomenon

Band Three Protein, an anion exchange protein

37

How are H+ ions carried in venous blood

Remain in RBC's buffered by deoxyHb

38

Rate limiting step of bicarb reaction

CO2 + H20 to H2CO3

39

Shape of CO2 vs O2 curve

O2 is s-shaped; CO2 is linear -> Changes in PCO2 over broad range will have same effect on CO2 content

40

Steepness of CO2 vs O2 curve

CO2 curve is much steeper --> Allows big changes in CO2 with changes in PCO2

41

Haldane Effect

Oxygenation of Hb decreases its ability to carry CO2 --> Shifts CO2 curve right

42

Ratio of excretion of HCO3 by the kidney relative to CO2 by the lung

[100mEq/day] / [10,000mEq/day]

43

pH in terms of HCO3 and CO2

pH = 6.1 + log[HCO3]/(0.03PCO2)

44

Small changes in Alveolar Ventilation have ____ effects on plasma pH

Pronounced