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

Question 1

Respiratory Quotient

Answer 1

Ratio of CO2 produced to O2 consumed

Question 2

Respriatory Quotient depends on

Answer 2

what we eat and burn

Question 3

Partial Pressure of inspired O2 vs dry air

Answer 3

159 vs 150

Question 4

Henry’s Law

Answer 4

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

Question 5

How do we measure diffusing capacity of lung

Answer 5

Single breath inhalation of carbon monoxide

Question 6

Diffusion rate of CO2 vs O2 in blood and tissue

Answer 6

CO2 diffuses 20 times faster than O2

Question 7

Solubility of CO2 vs O2

Answer 7

CO2 is about 23 times that of O2

Question 8

Partial Pressure of O2 in arterial system

Answer 8

100 mmHg

Question 9

Partial Pressure of O2 in venous system

Answer 9

40 mmHg

Question 10

Partial Pressure of CO2 in arterial system

Answer 10

40 mmHg

Question 11

Partial Pressure of CO2 in venous system

Answer 11

46 mmHg

Question 12

Partial Pressure of O2 in Alveolus

Answer 12

105 mmHg

Question 13

Partial Pressure of CO2 in Alveolus

Answer 13

40 mmHg

Question 14

What determines Alveolar PCO2

Answer 14

CO2 production in body/ Alveolar ventilation

Question 15

If CO2 production is constant, then PACO2 is determined by

Answer 15

Alveolar Ventilation

Question 16

How does cellular O2 consumption affect PAO2

Answer 16

Decreases, more O2 will leave alveoli and enter blood

Question 17

Alveolar Gas Equation

Answer 17

PAO2 = PIO2 - PACO2/R

Question 18

Definition of Hypoxemia

Answer 18

Arterial PO2 < 100mmHg

Question 19

A - a gradient is a measure of

Answer 19

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

Question 20

A - a gradient is useful for

Answer 20

examining causes of hypoxemia

Question 21

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

Answer 21

Acute Lung Injury

Question 22

What is used as a measure of Acute Lung Injury

Answer 22

Ratio of Arterial PO2 to Fraction of Inspired Oxygen

Question 23

Gas transfer is said to be ____-limited

Answer 23

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

Question 24

CO transfer is ____-limited

Answer 24

Diffusion limited

Question 25

What causes oxidation of Iron to Methemoglobin

Answer 25

Nitrites and Sulfonamides

Question 26

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

Answer 26

TRUE

Question 27

Typical percent saturation of Hb as it leaves most tissue capillaries

Answer 27

75%

Question 28

4 Causes of Decreased Hb affinity for O2

Answer 28

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

Question 29

4 Causes of Increased Hb affinity for O2

Answer 29

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

Question 30

What increases 2,3-DPG

Answer 30

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

Question 31

How does CO affect O2 affinity

Answer 31

Increase, making more difficult to release

Question 32

3 mechanisms for CO2 transport in blood:

Answer 32

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

Question 33

Amount of CO2 dissolved in blood is determined by

Answer 33

Henry's Law

Question 34

How does CO2 bind to proteins in blood

Answer 34

binds to amine goups

Question 35

Hamburger's Phenomenon

Answer 35

(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

Question 36

What causes Cl- shift in Hamburger's Phenomenon

Answer 36

Band Three Protein, an anion exchange protein

Question 37

How are H+ ions carried in venous blood

Answer 37

Remain in RBC's buffered by deoxyHb

Question 38

Rate limiting step of bicarb reaction

Answer 38

CO2 + H20 to H2CO3

Question 39

Shape of CO2 vs O2 curve

Answer 39

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

Question 40

Steepness of CO2 vs O2 curve

Answer 40

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

Question 41

Haldane Effect

Answer 41

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

Question 42

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

Answer 42

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

Question 43

pH in terms of HCO3 and CO2

Answer 43

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

Question 44

Small changes in Alveolar Ventilation have ____ effects on plasma pH

Answer 44

Pronounced