(17) Gas Transport (Karius) Flashcards
How is [Oxygen] Alveolar determined?
How much O2 can dissolve in water?
NOT MUCH!!!
Only 0.3 ml O2/dl blood
If the PaO2 is 100mmHg, each dL of blood will carry…
0.3 ml O2
In order to meet our metabolic demands (250 ml O2/min), our hearts would have to pump…
83 L of blood per min
When we refer to the PaO2, we are referring to…
the DISSOLVED OXYGEN
How does our body compensate for the low solubility of O2?
Use of HEMOGLOBIN
How many sites does hemoglobin have to bind to O2?
4
Important takeaways?
- Cooperative
- Increased affinity
- Non linear
At an PO2 greater than 60…
The Hb is at least…
85% saturated with oxygen
What is our typical oxygen content at 85% saturation?
17 ml O2/dl blood
What does a left shift represent on a Hb-O2 curve?
Increase in affinnity of Hb for O2
What does a right shift on the Hb-O2 curve represent?
Decrease in the affinity of Hb for O2
What factors can produce shifts in the Hb-O2 curve?
- CO2 and or pH (Bohr effect)
- Temperature
- Certain metabolites (2,3 DPG)
*Everything is Right shifted EXCEPT for low CO2/high pH
Where do we see an increase in…
CO2/H+
Temperature
2,3 DPG?
In the Tissue
Venous PO2 is…
40 mm Hg
What is the O2 saturation of venous blood?
Approx. 75%
15.2 ml O2/dl blood
Explains why we can do CPR
How do you determine how much oxygen was used by the tissue being perfused?
The difference between the
Arterial O2 content and the Venous O2 content
The greater the a-v O2 difference is…
The higher metabolic demand of the tissue
If the fuel is only carbohydrates…
There is a ______ ratio
1:1 Ratio
If the fuel is exclusively fats…
The ratio is ______
7: 10
(0. 7)
Usually a mix of fuels:
Carbohydrates and fats produces a…
____ ratio
0.8
How do you calculate the respiratory quotient (RQ)?
What is a normal respiratory quotent?
Answer
