Partial Pressure of Gases and Effects on Gas Exchange Flashcards Preview

Physiology 2130 > Partial Pressure of Gases and Effects on Gas Exchange > Flashcards

Flashcards in Partial Pressure of Gases and Effects on Gas Exchange Deck (16):
1

What is a partial pressure of a gas?

The pressure exerted by a single gas in a mixture of gases or while dissolved in a liquid
-each gas has its own partial pressure in air

2

What is the partial pressure of the O2 and CO2 at sea level ?

PO2= 160mmHg
PCO2= 0.3mmHg

3

What are 5 things that max simple diffusion?

1. Surface area
2. [gradient]
3. Membrane thickness
4. Molecule Size
5. Membrane composition

4

What are the alveolar partial pressures of O2 and CO2?

PO2= 100mmHg
PCO2= 40mmHg

5

What are the venular partial pressures of O2 and CO2?

PO2= 40mmHg
PCO2= 46mmHg

6

What is the equation for Ficks law of diffusion?

( [gradient]xSA) / Membrane thickness

7

Why is alveolar partial pressure different from outside?

Lungs contain "stale" air that already contain some O2 and CO2
-allows for the gradient

8

What does diffusion promote?

equilibrium
-exchange until all pressures are equal

9

What are the different components of blood?

<1% White blood cells
45% RBCs (erythrocytes)
55% Plasma (water, protein, ions, gases vits, waste)

10

How is O2 transported in the blood?

1. Disolved in plasma (1.5%)
2. Bound to hemoglobin inside erythrocytes (98.5%)

11

On average how much O2 is transported dissolved in plasma?

15mL, where the body needs 250mL of O2 at rest

12

What is hemoglobin?

Is a large protein found inside red blood cells

13

What is oxyhemoglobin?

When O2 attached reversibly with hemoglobin

14

Where does O2 bind in hemoglobin?

O2 binds to the Fe which is bound to the heme within one of the globing subunits

15

How does heme decide to keep or lose an O2?

Influenced by partial pressure of O2 which dictates if heme keeps or releases O2

16

What is the oxyhemoglobin dissociation curve?

S shaped curve, at the bottom/middle there is a high slope which leads to quick saturation changes. At the top it is pretty flat and there won't be as quick changes in saturation
-changes the amount of O2 left on heme