Oxygen Transport Flashcards
How much of O2 is dissolved in plasma?
1.5%
PaO2 is directly proportional to what?
dissolved O2 in plasma
What is the structure of a hemoglobin molecule?
4 heme and 1 globin molecule
How many oxygen molecules can bind to a hemoglobin?
4
True or False: CO2 binds to the same site that oxygen binds to
False
What is critical for O2 binding to globin?
the amino acid sequence
Why is fetal hemoglobin so great?
it has a higher affinity to oxygen and can manage some form of hypoxia
What causes nitrate poisoning?
Fe(2+) and Fe(3+)
What does CO + Hb make?
carboxyHb
True or False: CO occupies the same site as O2.
true
CO has ___ times more affinity than O2.
200
Is O2 binding with heme reversible or irreversible?
reversible
What is the law of mass action?
the products formed are proportionate to the reaction
What determines % Hb saturation?
PO2
What is allosteric (cooperativity)?
when a hemoglobin already has oxygen bound to it, it will attract more oxygen to the area rather than that oxygen going to an empty hemoglobin
How many mL of O2 binds with 1 g of Hb?
1.34-1.39
What percent saturation is mixed venous blood?
60%
What does PvO2 equal normally?
40 mmHg
What pressure is 50% saturation at?
25 mmHg
How do you determine CaO2?
CaO2 = (PaO2) + (1.39 x mmHg Hb X % saturation)
What is PiO2?
inspired oxygen
What is PaCO2?
arterial CO2
What is PaO2?
arterial O2
When does A-a increase ?
aging, VQ mismatches, shunt, and diffusion impairment
How is A-a measured?
pulse oximetry (SpO2), arterial blood gas analysis, A-s equation
How does pulse oximetry work?
•Refracts light (red and infared) through region to see hemoglobin saturation, Oxyhemoglobin absorbs the infared light and the red light passes through
What is the A-a equation?
A-a= [P1O2 - (PaCO2/0.8)-PaO2]
How does O2 diffuse into tissues?
Leaves hemoglobin, then goes into the plasma, then the concentration gradient forces them out into the tissues
What does a left shift mean in the O2 saturation chart?
Hb will hold onto the O2 making the delivery of O2 more difficult.
What does a right shift mean in the hemoglobin O2 saturation chart?
Hb affinity for O2 decreases, the delivery of O2 is facilitated
What causes a right shift in the hemoglobin-O2 saturation chart?
drop in pH, increase in temp, increase in PCO2, increase in 2,3 DPG
What causes a left shift in the hemoglobin-O2 saturation chart?
increase in pH, drop in temp, drop in PCO2, drop in 2,3 DPG
Why does PCO2 change the pH?
there is a hydration reaction, H+ changes the pH; favored in RBCs
Where is 2, 3 DPG present?
in red blood cells (product of glycolysis)
Why is CO lethal?
when present, it steals O2’s spot and therefore no oxygen can be absorbed
What are the main acids that we make in the body?
lactic and carbonic acids
