S3_L5: Gas Transport Flashcards
TRUE OR FALSE: Of the O2 that diffuses from the alveoli, 97.5% combines with hemoglobin and 1.5% dissolves in plasma
False, its 98.5% that combines with hemoglobin
When four O2’s are bound to hemoglobin, it is ___% saturated, and with fewer O2’s, it is partially saturated.
100
Hemoglobin molecule can transport up to 4 O2’s
Number of iron atoms in 1 hemoglobin molecule
Four
4 O2’s will bind to the 4 iron atoms
TRUE OR FALSE: Hemoglobin’s affinity for O2 increases as O2’s saturation decreases
False, there’s a direct relationship between the affinity of hemoglobin & oxygen saturation
This is used to determine how much partial pressure of oxygen could make the hemoglobin be filled/saturated at a certain amount of blood pressure
Oxygen-Hemoglobin Dissociation Curve
TRUE OR FALSE: When O2 is unbounded at tissue level, oxyhemoglobin (Hb O2) becomes deoxyhemoglobin (Hb)
True
Hb + O2 -> Hb O2
The oxygen-hemoglobin dissociation curve is an S-shaped curve with a (1)___ slope at high PO2’s and (2)___ slope at lower PO2’s.
- flat
- steep
TRUE OR FALSE: The PO2 is lower in vigorously contracting muscles than in resting muscles
True
Because more O2 is unloaded to the working muscles
TRUE OR FALSE: Exercise increases the pH, which increases acidity, causing a release of lactic acid
False, exercise decreases the pH
TRUE OR FALSE: Exercise increases temperature, PCO2, and bisphosphoglycerate (BPG)
True
The Oxygen-Hemoglobin Dissociation Curve shifts to ___ when exercising due to decreased pH, increased temperature, PCO2, and BPG.
right and downwards
-increased oxygen unloading, unload O2 at a faster rate, 95 or 93% saturated
The Oxygen-Hemoglobin Dissociation Curve shifts to the ___ as a response to decreased temperature, PCO2, BPG, and increased pH.
Left and upwards
-At decreased temperatures, hemoglobin’s affinity for oxygen is higher and less oxygen is released, which favors O2 conservation and the blood becomes alkaline. 85% saturated
Enumerate the 3 ways of CO2 transport from tissue cells:
- Dissolved in plasma (7%)
- Bound to hemoglobin as carbaminohemoglobin (23%)
- Converted to bicarbonate ions (70%)
Carbaminohemoglobin forms in regions of ___ PCO2
high
TRUE OR FALSE: In the lungs with lower PCO2, carbon dioxide dissociates from carbaminohemoglobin and returns to H20+CO2. Then, CO2 diffuses into the alveoli.
True
In regions with high PCO2, CO2 enters the RBC and binds with H2O from the RBC to form carbonic acid. This reaction is catalyzed by this enzyme.
carbonic anhydrase
In the plasma, ____ acts as a buffer to control blood pH.
bicarbonate ions
Plasma & RBC become acidic since there are lactic acid and free flowing hydrogen ions
there. As this should not happen, bicarbonate ions will buffer the plasma by exiting & exchanging with chloride ions to maintain electrical neutrality (chloride shift occurs).
As carbonic acid is unstable, it will dissociate into ___ and ___.
hydrogen ions and bicarbonate ions
TRUE OR FALSE: When hemoglobin is saturated with oxygen, its affinity for carbon dioxide increases.
False, its affinity for carbon dioxide decrease
Oxygen loading facilitates carbon dioxide unloading from hemoglobin
___ is the interaction between O2 loading and CO2 unloading from hemoglobin at the alveolocapillary level. Once O2 combines with hemoglobin, there is the H2 that is bounded to hemoglobin because of CO2 transport. O2 will kick out H2 and H2 will combine with CO2 later on.
Haldane Effect
___ is the interaction between hydrogen ion binding and hemoglobin’s affinity for oxygen: CO2 loading, through the formation of hydrogen ions, facilitates O2 unloading from hemoglobin. It is the effect of decreased pH on O2 unloading.
Bohr Effect
In regions with low PCO2, such as the lungs, carbonic acid breaks down into CO2 and water. This reverse reaction is catalyzed by ____.
carbonic anhydrase
In the reverse reaction in the lungs, ___ breaks down into CO2 and H2O. As PCO2 is higher in the RBC than the alveolus, CO2 will diffuse toward the alveolus and H2O will remain in the RBC.
carbonic acid
