Unit 2 L7 Gas Transport Flashcards
O2 is carried in the blood in 2 forms
Dissolved
Bound to hemoglobin
PAO2 defintion
Alveolar partial pressure of oxygen
PaO2 defintiion
Arterial partial pressure of oxygen (dissolved)
SaO2 definition
Oxygehmoglobin or hemoglobin saturation, so the percentage of hemoglobin sites with oxygen bound. This is dictated by PaO2 and PvO2
CaO2 definition
Oxygen content, oxygen concentration. Total oxygen in the blood per unit volume, aka dissolved oxygen + oxyhemoglobin
How can we go from PAO2 to total oxygen in the blood?
PAO2 gives us PaO2, which gives us SaO2, which gives us CaO2. In other words, PO2 –> [O2] dissolved –> O2-Hb% –> total oxygen in blood
The amount of dissolved oxygen in the blood dictates ______
How much oxygen is bound to hemoglobin
PO2 does not directly tell us what
How much oxygen is in the blood
Dissolved oxygen is measured clinically as
PaO2
Henry’s law of gas solubility
C = KHP
Dissolved oxygen gives us how much O2 per min
15 mL O2 per min
How much oxygen do we need per minute
250 mL O2/min
Is dissolved O2 alone enough for us to live
lol no
If we have 100% oxygen, does that give the dissolved oxygen enough to be what we need
lol no
Hemoglobin has how many heme groups
4
Oxygenated blood is what color
R E D
Deoxygenated blood is what color
B L U E
Tense state
No oxygen bound, low affinity for oxygen
Relaxed state
Oxygen bound, high affinity
Oxygen binding is what kind of binding
Cooperative
Arterial blood Hb saturation is what percentage
98%
Venous blood Hb saturation is what percentage
75%
At PO2 > 60, what kind of changes are there in Hb saturation
Small changes in Hb saturation. Facilitates normal O2 transport to organs/cells
At PO2 < 60 mmHg, small changes in pressure lead to what
Release of large amounts of O2. Facilitates release to organs/cells
What is the significant threshold for hypoxemia intervention
60 mmHg
Left shift of the Hb curve means what for O2 binding
Increased Hb-O2 binding
Right shift for Hb curve means what for O2 binding
Decreased Hb-O2 bidning
What will shift the curve left
Decrease in temp, PCO2, and 2,3-DPG
Increase in pH
What will shift the curve right
Increase in temp, PCO2, and 2,3-DPG
Decrease in pH
What is the cheat code
As factor X increases, Hb binding of oxygen decrease (temp, CO2, H+, 2,3-DPG)
Everything except CO
2,3-DPG will what
Preferentially bind to de-oxygenated Hb and decreases affinity of Hb for oxygen
What factors together provide the greatest shift of the Hb curve?
CO2 and DPG together
Affinity of CO for Hb is _________ compared to affinity of O2
> 200 times greater compared to affinity of O2
In the presence of CO, what happens to O2
Affinity for O2 is enhanced and unloading is prevented
CO will force Hb into what state
The relaxed state, so higher affinity for O2
Sickle cell disease
Single AA substitution in beta chain, HbS is normal with oxygen, will crystalize at low oxygen
Hemoglobin and diabetes
Hemoglobin A1c, so increased blood glucose means more G6P, so more glycosylated Hb
PaO2 > 80 mmHg means what
HYPOXEMIA
PaO2 = 60 mmHg means what
DANGER !!!
What is just as dangerous as altering your oxygen intake
Altering Hb saturation
To calculate the oxygen content in the arterial blood (CaO2)
Multiply O2 capacity by the SO2
Normal blood has what content at 100% saturation
20.1 mL O2/100 mL at SO2 100%
CO2 is carried in the blood in 3 forms
Dissolved
Bicarbonate
Carbamino compounds
Is there more dissolved CO2 or O2?
There is 20 times more dissolved CO2 than O2
Increasing PO2 does what for Hb affinity for CO2
Decreases Hb affinity for Co2
Decreasing PO2 does what for Hb affinity for CO2
Increases
Haldane effect
Effect of O2 on Hb to increase/decrease CO2 binding. Unloading of CO2 in lungs
Bohr effect
Effect of CO2 on Hb to increase/decrease O2 binding. Unloading of O2 in tissue
Anemic hypoxia is what
Reduction in capacity of blood to carry oxygen
Diffusion hypoxia
Reduction in circulation and subsequent oxygen delivery
Histotoxic hypoxia
Tissues are poisoned, not able to use oxygen
