Partial Pressure of Gases and Effects on Gas Exchange Flashcards
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
What is the partial pressure of the O2 and CO2 at sea level ?
PO2= 160mmHg PCO2= 0.3mmHg
What are 5 things that max simple diffusion?
- Surface area
- [gradient]
- Membrane thickness
- Molecule Size
- Membrane composition
What are the alveolar partial pressures of O2 and CO2?
PO2= 100mmHg PCO2= 40mmHg
What are the venular partial pressures of O2 and CO2?
PO2= 40mmHg PCO2= 46mmHg
What is the equation for Ficks law of diffusion?
( [gradient]xSA) / Membrane thickness
Why is alveolar partial pressure different from outside?
Lungs contain “stale” air that already contain some O2 and CO2
-allows for the gradient
What does diffusion promote?
equilibrium
-exchange until all pressures are equal
What are the different components of blood?
<1% White blood cells
45% RBCs (erythrocytes)
55% Plasma (water, protein, ions, gases vits, waste)
How is O2 transported in the blood?
- Disolved in plasma (1.5%)
2. Bound to hemoglobin inside erythrocytes (98.5%)
On average how much O2 is transported dissolved in plasma?
15mL, where the body needs 250mL of O2 at rest
What is hemoglobin?
Is a large protein found inside red blood cells
What is oxyhemoglobin?
When O2 attached reversibly with hemoglobin
Where does O2 bind in hemoglobin?
O2 binds to the Fe which is bound to the heme within one of the globing subunits
How does heme decide to keep or lose an O2?
Influenced by partial pressure of O2 which dictates if heme keeps or releases O2
