Flashcards in Quiz 5 Transport of Oxygen & Carbon Dioxide Deck (42):
What is the tissue pressure for O2 at the capillaries?
PO2 > 10 mm Hg
What is the tissue pressure for CO2 at the Capillaries?
PCO2 > 50 mm Hg
Diffusion is too slow over what distance?
> 100 um
What is hypoxic hypoxia?
-inadequate O2 uptake into blood in lungs
-Chronic obstructive pulmonary disease
What is stagnant (ischemic) hypoxia?
-inadequate blood flow to an organ
-Arteriosclerosis peripheral vascular disease
What is anemic hypoxia?
-Inadequate blood oxygen carrying capacity
What is histotoxic hypoxia?
-Interference with mitochondrial respiration
What is diffusion disturbance?
-Long diffusion path
What is the normal hemoglobin concentration?
-15 g/dL or 150 g/L
What are the four subunits of hemoglobin?
Normal adult HgbA has both A2 + B2
How much O2 can be carried by each gram of hemoglobin?
-1.31 mL of O2 (theoretically up to 1.39 mL/gm)
T/F: Hemoglobin is oxygenated.
T/F: Oxyhemoglobin is oxygenated.
What is oxygen saturation?
Ratio of oxygen bound to Hb compared to total amount that can be bound.
What is oxygen capacity?
Maximal amount of O2 bound to Hemoglobin.
What is the PaO2 when saturation (Hb) is 90%?
PaO2 = 60
What is the PaO2 when the saturation (Hb) is 75%?
What is the Pa02 when the saturation (Hb) is 50%?
PaO2 = 27
What is Ligand of hemoglobin?
-covalent bonds to the iron in Hemoglobin
-the bonds have more affinity to iron in hemoglobin than does oxygen
Carbon monoxide binds ______ times stronger to hemoglobin than oxygen.
-250 times the affinity then oxygen
-does not dissociate readily
-Requires hours to rid body of CO
Nitric oxide binds ______ times stronger to hemoglobin than oxygen.
-200,000 times the affinity then oxygen
-hemoglobin binds irreversibly to NO
-Used to treat hypertension
What factors would create a left shift of the Hb-O2 dissociation curve?
-Low PCO2 (alkalosis)
-Low levels of 2,3 DPG
What factors would create a right shift of the Hb-O2 dissociation curve?
-High levels of 2, 3 DGP
What type of shift would you see on Hb-O2 disassociation curve after a blood transfusion?
A left shift - PRBC are stored cold and are low in 2,3 DPG
Packed red blood cells have a diminished level of what?
What is the normal CO2 production in a resting adult?
What are the three forms carbon dioxide is transported by the blood?
1. Dissolved directly in blood.
2. Bicarbonate ion (HCO3-) and Carbonic acid (H2CO3).
3. Bound to hemoglobin and plasma proteins.
In what form is most CO2 transported by in the blood?
What is the P50 of oxygen PO2?
P50 - the pressure of Oxygen PO2 when your hgb is 50% saturated.
P50 = 27mmHg
Venous hgb has a PO2 of 40mm Hg, what is it's O2 Sat?
If you have a change in shape of the S-curve of the Oxyhemoglobin Curve, what does this indicate?
greater interference with O2 transport than a shift in the curve
Which has a greater affinity for oxygen, hemoglobin or myoglobin?
Myoglobin - binds O2 at lower PO2
What is Bohr effect?
An increase in H+ decreases Hgb's affinity for O2 (right shift)
What is the equation for CaO2 (O2 content of the blood)?
CaO2 = (SO2 * Hgb * 1.31) + (PO2 * 0.003)
SO2 will be expressed as decimal rather than %
In the equation for CaO2, what does the 1.31 represent?
the amount of O2 (1.31 ml) that 1 gm of Hgb can carry.
What is the Haldane effect?
O2 binds to Hgb --> Hgb releases CO2 and H+
What is the rough way to estimate PaO2 to SaO2?
PaO2: 40,50,60 ~ SaO2 70,80,90 %
Give an example of Hypoxic Hypoxia
Give an example of Stagnant (ischemic) hypoxia
Give an example of Anemic Hypoxia
hypoxia due to anemia - inactivated hemoglobin.
Give an example of Histotoxic Hypoxia
hypoxia due to cyanide poisoning