Quiz 5 Transport of Oxygen & Carbon Dioxide Flashcards
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
- Inactivated hemoglobin
What is histotoxic hypoxia?
- Interference with mitochondrial respiration
- Cyanide poisoning
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?
- 2 alpha
- 2 beta
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.
False
T/F: Oxyhemoglobin is oxygenated.
True
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%?
PaO2 =40
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 temperature
- Low levels of 2,3 DPG
- carboxyhemoglobin
- methemoglobin
- abnormal hemoglobin
What factors would create a right shift of the Hb-O2 dissociation curve?
- Acute acidosis
- High CO2
- Increased temperature
- High levels of 2, 3 DGP
- Abnormal hemoglobin
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