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
Perfusion wil change to match []. Ventilation [] [] change to match perfusion.
ventilation; DOES NOT
- Is blood flow [higher/lower] in the [apex or base] of the lungs?
- Is Alveolar ventilation [higher/lower] in the [apex or base] of the lungs?
- higher in the base
- higher in the base
T/F
If you’re lungs have an increase in perfusion and a decrease in ventilation this will cause local levles of PCO2 to rise and PO2 to fall….the pulmonary arterioles would dilate to compensate for this.
FALSE
the pulmonary arterioles have to match ventilation with perfusion. So if ventilation goes down, then perfusion would have to go down…therefore the arterioles would need to constrict and block of the perfusion.
T/F
If you’re lungs have a decrease in perfusion and an increase in ventilation this will cause local levels of PCO2 to fall and PO2 to rise….the pulmonary arterioles would dilate to compensate for this.
TRUE!
The arterioles need to match perfusion to ventilation. Since, ventilation has increased we need more blood to the area so the vessesl will dilate.
As oxygen binds ot hemoglobin, it changes shape making its affinity for oxygen [] .
higher
Loading and unloading of O2 is facilitated by change in shape of [].
- As O2 binds, HB affinity for O2 []
- As O2 is released, Hb affinity for O2 [].
Hemoglobin
- increases
- decrease
Hemoglobin is fully saturated if….
All 4 heme groups have a bound Oxygen molecule
The rate of loading and unloading of O2 is regulated by….
PO2
Temperature
Blood pH
PCO2
Conecntraion of BPG
A right shift in the oxygen dissociation curve can take place due to….
- [] in PCO2 and [] in pH
- [] in temperature
- [] in 2,3-DPG concentration
- Increases in PCO2 and decreases in pH
- Increases in temperature
- Increases in 2,3-DPG concentration
A left shift in the oxygen dissociation curve can be caused by…
- [] in PCO2 and [] in pH
- [] in temperature
- [] in 2,3-DPG concentration
- decrease in PCO2 and increase in pH
- decrease in temperature
- decrease in 2,3-DPG concentration
- A right shift in the oxygen dissociation curve means that hemoglobin has [] affinity for O2, which leads to [] unloading
- A left shift in the oxygen dissociation means that hemoglobin has [] affinity for O2, which leads to [] unloading.
- less affinity; more unloading
- More affinity; less unloading
Bohr Effect:
- the lower the pH in the blood, the [] oxygen binds to []
- Resulting in more oxygen being [] in tissues that need it most
- the lower the pH in the blood, the weaker oxygen binds to hemoglobin
- Resulting in more oxygen being unloaded in tissues that need it most
Haldane Effect:
- the [] oxygen bound to hemoglobin, the [] carbon dioxide that can bind to hemoglobin
- This enhances the [] of carbon dioxide from highly active tissues
- the less oxygen bound to hemoglobin, the more carbon dioxide that can bind to hemoglobin
- This enhances the removal of carbon dioxide from highly active tissues
Only []-[]% of bound O2 is unloaded during one systemic circulation.
20-25%
So like 1/4 Oxygen per RBC?
T/F
If O2 levles in tissues drop, respiratory rate or cardiac output is immediately increased.
FALSE
Respiratory rate and cardiac output nee dnot increase….more oxygen can dissoaciate from hemoglobin. Since, in normal condition, only 20-25% of oxygen is unloaded during one systemic circulation.
What is CO2 bound to hemoglobin called?
Carbaminohemoglobin
CO2 transport
- [] % is dissolved in plasma
- [] % is bound to globin in hemoglobin
- [] % as bicarbonate ions in the plasma
- 5 % is dissolved in plasma
- 5 % is bound to globin in hemoglobin
- 90 % as bicarbonate ions in the plasma
T/F
As bicarbonate is transferred through the body, it diffuses out of RBC and into the plasma in order to act as a buffer?
TRUE
T/F
The chloride shift occurs to balance pH in the cell/plasma.
FALSE
The chloride shift occurs to maintain electrical charge as the bicarbonate leaves the cell.
In what two “general” locations does the chloride shift take place?
What is going into/coming out of the cell in each location?
- At the tissues
- Bicarbonate diffuses out of the RBC into the plasma
- Chloride comes into the cell
- At the lung alveoli
- Bicarbonate diffuses into the RBC from the plasma (to be converted to CO2 and then expired from alveolar cell)
- Chloride leaves the cell.
