Respiratory 3

Question 1

Gases, just like ions and water, move according to the principles of _____

Answer 1

diffusion.

Question 2

After gas exchange in the pulmonary capillaries,PO2 is actually 95 mmHg due to ______

Answer 2

bronchial circulation.

Question 3

After gas exchange in the pulmonary capillaries,PO2 is actually ___ mmHg due to bronchial circulation.

Answer 3

95 mmHg

Question 4

______ refers to the pressure of one gas in a mix.

Answer 4

Partial Pressure (Pgas)

Question 5

At normal alveolar ventilation and O2 absorption rates (250 ml/min), PAO2 is ____ mmHg.

Answer 5

100 mmHg

Question 6

Increasing alveolar ventilation will ____ PAO2.

Answer 6

increase

Question 7

To calculate a partial pressure in a liquid solution, the ____ and _____ of the gas are required

Answer 7

relative concentration and the solubility coefficient

Question 8

This addition of water ______ the partial pressure of all other gases.

Answer 8

decreases

Question 9

Attractability of molecules to water. If this number is high, the gas diffuses quickly.

Answer 9

Solubility Coefficient.

Question 10

Henry’s Law–Partial Pressure =

Answer 10

PP= Concentration of Dissolved Gas/Solubility Coefficient

Question 11

At a constant temperature, the amount of a gas that dissolves in liquid is ______ to the partial pressure and the solubility.

Answer 11

directly proportional

Question 12

Gas Exchange at the Respiratory Membrane Depends on what 2 things?

Answer 12

1. Transport rate through the respiratory membrane.

2. The rate of alveolar ventilation

Question 13

An increase in alveolar ventilation will _____ PAO2 and gas exchange with an upper limit of 150 mmHg (the PAO2of humidified air.

Answer 13

Increase

Question 14

What 3 factors increase the volume of gas diffusing through the tissue barrier per unit time?

Answer 14

1. Difference in Partial Pressures Across the Membrane (ΔP )
2. Solubility of Gas in Fluid (S)
3. Cross-Sectional Area of Membrane (A)

Question 15

What 2 factors decrease the volume of gas diffusing through the tissue barrier per unit time?

Answer 15

4. Distance of Diffusion (d)

5. Molecular Weight of Gas (MW)

Question 16

A tissue with high metabolic activity will have a ____ PO2, creating a ____ partial pressure gradient.

Answer 16

lower; larger

Question 17

CO2 is ____ soluble (S) than O2so CO2 diffusion occurs ____ rapidly

Answer 17

more; more

Question 18

If more pulmonary capillaries are recruited, as in exercise, the surface area (A) available for diffusion _____

Answer 18

increases

Question 19

If the thickness of the diffusion barrier increases (d), such as with Pulmonary Fibrosis or Edema, this _____ diffusion.

Answer 19

decreases

Question 20

What are the 6 components of respiratory membrane?

Answer 20

1. Surfactant
2. Alveolar Epithelium
3. Alveolar Basement Membrane
4. Interstitial Space
5. Endothelial Basement Membrane
6. Capillary Endothelium

Question 21

Average width of respiratory membrane is ____ μm

Answer 21

0.6 μm

Question 22

Under normal conditions, O2 transport into pulmonary capillaries is _____-LIMITED

Answer 22

PERFUSION-LIMITED

Question 23

under other conditions (fibrosis, emphysema, strenuous exercise),O2 transport into pulmonary capillaries can become _____-LIMITED.

Answer 23

DIFFUSION-LIMITED

Question 24

Measures respiratory membrane’s functional integrity; Amount of a gas entering pulmonary blood per unit time (ml/min/mmHg)

Answer 24

Diffusing capacity of the lung (DL)

Question 25

DLCO2 cannot be calculated because of its ______

Answer 25

rapid diffusion

Question 26

DLO2 is also difficult to calculate since most of O2 binds to ______

Answer 26

hemoglobin

Question 27

______ is ideal for DL since it is diffusion-limited.

Answer 27

Carbon monoxide

Question 28

Decreased Surface Area (A) or Increased Distance of the diffusion barrier (d), will ____ gas diffusion.

Answer 28

decrease

Question 29

What 3 things could an abnormally low DLCO test indicate?

Answer 29

1.  Thickening of the Barrier (increased d)
–Interstitial edema or fibrosis
2.  Decreased Surface Area (decreased A)
–Emphysema
–Low Cardiac Output
–Tumors
–Ventilation-Perfusion Mismatch
3.  Decreased Uptake
–Anemia
–Decreased blood volume in pulmonary capillaries

Question 30

1. Thickening of the Barrier (increased d) can be caused by ____ or _____

Answer 30

–Interstitial edema or fibrosis

Question 31

2. Decreased Surface Area (decreased A) can be caused by what 4 things?

Answer 31

–Emphysema
–Low Cardiac Output
–Tumors
–Ventilation-Perfusion Mismatch

Question 32

3. Decreased Uptake can be caused by what 2 things?

Answer 32

–Anemia

–Decreased blood volume in pulmonary capillaries

Question 33

Someone with a thickened alveolar membrane (pulmonary fibrosis) will have ____ limited oxygen transfer at rest and it will be an even more pronounced limitation with exercise

Answer 33

diffusion limited O2 transfer

Question 34

Calculation of PAO2 is important because you can compare the value to PaO2. A large difference indicates a problem with diffusion.

Answer 34

A-a gradient

Question 35

Normal A-a gradient is ___ mmHg in a young, non-smoker.

Answer 35

5-10

Question 36

The A-a gradient increases by ___ mmHg for each decade so a normal value for a 40 year old would be

Answer 36

1; 14

Question 37

A good estimate for a normal A-a gradient is (formula)

Answer 37

Age/4 + 4

Question 38

PAO2 is predicted based on what 3 things?

Answer 38

1. The partial pressure of O2 inspired
2. The PaCO2
3. The ratio of CO2 produced/O2consumed—the respiratory quotient

Question 39

______ is the ratio of CO2 produced (200 ml/min) divided by the O2 consumed (250 ml/min)

Answer 39

Respiratory quotient (RQ)