Respiratory - Pt 4 Gas Exchange Flashcards
What is the equation for Boyle’s Law?
P1V1 = P2V2
What is the equation for Dalton’s Law of Partial Pressures?
What does each variable stand for?
Px = (PB-PH2O) * F
- Px - Partial Pressure of gas (mmHg)
- PB - Barometric Pressure (mmHg)
- PH2O - Water Vapor Pressure @ 37 C = 47 mmHg
- F = fractional concentration of gas.
- Ex: O2 in our atmosphere is 21%, so .21
O2 atmospheric percentage is always []%, doesnt matter if you in Colorado, KY, or in your lungs.
21%
What is the water vapor pressure @ 37 degrees C?
47 mmHg
Partial pressure is due to the gas that is [] in plasma, not the gas that is [].
Partial pressure is due to the gas that is dissolved in plasma, not the gas that is bound.
- PO2 in blood is roughly []-[] mmHg in blood
- CO binds to hemoglobin with []% more affinity than oxygen
- Can affect the bound [] by altering the []
- PO2 in blood is roughly 98-100 mmHg in blood
- CO binds to hemoglob with 400% more affinity than oxygen
- Can affect the bound O2 by altering the PO2
T/F
CO2 is more soluble than O2 in blood.
TRUE
O2 is 1/20 of the solubleness that CO2 is!
What is the equation for Fick’s Law of Gas Exchange? And what does each variable stand for?
V ~~ D * A/T * (P1 - P2)
- V = Rate of gas movement
- D = Diffusion constant
- A = Surface are for diffusion
- T = Thickness of alveolar-capillary membrane
- P1 - P2 = Partial pressure gradient of the gas.
The driving force for diffusion of a gas is the [] [] [] [] [] [] across the membrane and not the [] difference.
The driving force for diffusion of a gas is the partial pressure difference of the gas across the membrane nad not the concentration difference
- Venous blood PO2 = [] mmHg
- Alveolar PO2 = [] mmHg
- O2 partial pressure reaches equilibrium in about [] of the time a red blood cell is in a pulmonary capillary.
- 40 mmHg
- 104 mmHg
- 1/3 of the time
Alveoli Pressures -> Capillary Blood PO and PCO2
- Alveoli PO2 –> Capillary PO2
- Capillary PCO2 –> Alveoli PCO2
- 100 mmHg –> 40 mmHg
- 46 mmHg –> 40 mmHg
Arterial Circulation…
PO2 = ?
PCO2 = ?
PO2 = 100 mmHg
PCO2 = 40 mmHg
Venous Circulation…
PO2 = ?
PCO2 = ?
PO2 = 40 mmHg
PCO2 = 46 mmHg
What are the 3 factors affecting external respiration?
- Partial pressure gradients and gas solubility
- Matching of alveolar ventilation
- Structural characteristics of the respiratory membrane
Ventilation-Perfusion Coupling
- Ventilation: amount of [] reaching the alveoli
- Perfusion: [] reaching the alveoli
- Ventilation and Perfusion must be [] for [] gas exchange
- Ventilation/perfusion ratio is used []/ []
- Ventilation: amount of gas reaching the alveoli
- Perfusion: Blood flow reaching the alveoli
- Ventilation and Perfusion must be matched for efficient gas exchange
- Ventilation/perfusion ratio is used V/Q