F - Gas Transport - Karius

Question 1

Alveolar oxygen is

Answer 1

The oxygen in lungs minus the oxygen used by tissue

Question 2

Solubility of O2

Answer 2

Limited solubility in water and therefore plasma

0.3 ml O2/dl blood/100 mmHg

Question 3

What does the solubility of O2 number mean?

Answer 3

If PaO2 is 100 mmHg, each dl of blood will carry 0.3 ml O2
*In order to meet this demand hearts would have to pump 83 liters of blood/min - solution is hemoglobin
PaO2 refers to the dissolved oxygen

Question 4

Hb is how saturated with a PO2 > 60 mmHg?

Answer 4

85% saturated

-enough to supply metabolic demands

Question 5

What are some factors that cause a right shift (decreased) in O2 curve? And where do you normally see this?

Answer 5

Fever, high CO2 or low pH, 2,3-DPG

Normal in the tissues so O2 leaves Hb

Question 6

Is all oxygen taken up by the tissue?

Answer 6

No, as indicated by the PO2 of 40 mmHg

-

Question 7

What is the oxygen saturation of venous blood? And what would the O2 content be?

Answer 7

75%

O2 content = 20.1 x 75% = 15.2 ml O2/dl blood

Question 8

a-v O2 difference

Answer 8

How much oxygen was used by the tissue being perfused
*19.8 - 15.2 = 4.6
Dependent on tissue need
Ex. fat needs little, skeletal m. a lot

Question 9

Metabolic processes in the cell results in

Answer 9

CO2 + H2O + Heat

Question 10

Ratio of O2 to CO2 if the fuel is carbohydrates

Answer 10

1:1 ratio

Question 11

Ratio of O2 to CO2 if the fuel is fats

Answer 11

7:10

7 CO2s produced for every 10 O2 consumed

Question 12

Ratio of O2 to CO2 if the fuel is mix of fuels

Answer 12

8:10 = .8

200 CO2s produced for every 250 O2s consumed

Question 13

Respiratory Quotient

Answer 13

The ratio between CO2 produced and the O2 consumed

Equation = RQ = Volume of CO2 produced divided by volume of O2 consumed

Question 14

Solubility of CO2

Answer 14

Has greater solubility in water (plasma)

6 ml O2/dl blood/100 mmHg (vs. .3 for O2)

Question 15

PCO2 of venous blood

Answer 15

45 mmHg

Question 16

Haldane Shift

Answer 16

The presence of O2 on the heme reduces the affinity of the Hb chain for the CO2

Question 17

Amount of CO@ carried in carbamino compounds

Answer 17

3ml/dl

7%

Question 18

Most of the cO2 in the blood is carried as

Answer 18

Bicarbonate (HCO3)

86% - 44 ml of CO2

Question 19

The chloride shift

Answer 19

In venous blood

H2O goes in and carbonic anhydrase(HCO3) is transported out of the cell with an anti porter that takes Cl- into the cell

Question 20

HCO3 converted back to what in the lungs?

Answer 20

CO2
CO2 is then free to diffuse into the alveoli
Many of the H+ are displaced from the Hb as oxygen starts to bind

Question 21

PAO2 calculation

Answer 21

Alveolar partial pressure of O2

PlO2 ((760 - 47) x O2%) - PaCO2/0.8

Question 22

A-a O2 gradient

Answer 22

PAO2 - PaO2
-useful in determining the health of the alveoli
Normal < 20 mmHg

Question 23

An increase in A-a O2 gradient indicates

Answer 23

A diffusion impairment