17. Gas Transport Flashcards
[oxygen]alveolar= ? - ?
[oxygen in]lungs (100mmHg) - [oxygen used] by tissue (tissue O2 consumption)
Since O2 has a limited solubility in water/plasma, what is the solublilty of O2?
0.3mL/dLblood/100mmHg
meaning if PaO2 is 100mmHg, then each dL of blood will carry 0.3 mL O2
How many liters of blood per minute would our heart have to pump in order to meet our metabolic demands of 250mlO2/min?!?!
83 liters of blood per min (lol)
What are we reffering to when we say the PaO2 in arterial blood?
Reffering to dissolved oxygen
Hemoglobin is used and an equilibrium between the plasma and Hb is acheived, allowing for?
Us to get the rest of the O2 needed
Hb-O2 dissociation curve: As oxygen in mmHg in arteries increases, so does the Hb saturation. What is unique about the Hb O2 dissociation curve?
Cooperativity. As one O2 binds to Hb, a conformational change occurs leading to a second to bind, to a third and fourth.
At PaO2 greater than 60mmHg, the Hb is at least?
saturated at 85%, meaning our oxygen content is at least 20.1mlO2/dlblood (cardiac output) x .85 = 17mL/O2/dLblood meeting the metabolic demands
What occurs during a left shift of the Hb-O2 curve of HbA?
A left shift increases the affinity of Hb for O2 (remember to add in amount of O2 dissolved (0.3/100mmHg) with the amount Hb accounts for)
What does a right shift represent in the Hb-O2 curve?
A decrease in affinity of Hb for O2
What changes make a right shift
High CO2 BOHR EFFECT
Low pH
Increased Temperature
Increased 23DPG
What changes make a left shift?
Low CO2
High pH (low H+)
Decreased temp
Decreased 23DPG
When is altering the Hb-O2 curve needed/necessary?
To get o2 in the Tissue
O2 is released into the tissue from capillaries where it is used in metabolic processes to produce?
Heat, H20, and CO2
Not all O2 is taken up by the tissue, as indicated by the venous PO2 being?
40mmHg (compared to PaO2 being near 100)
O2 saturation of venous blood is about 75%. How do you calculate the O2 content?
20.1 mL/O2/dLblood x .75% = 15.2 mL/O2/dLblood
20.1mL/O2/dL blood is WHAT?
The oxygen content when Hb-O2 curve is near 100%
So the difference between artery and venous O2 content is representitive of the amount of O2 used in the tissue, which varies from tissue to tissue depending on the activity of each area. What is the average O2 used in the tissue?
20.1 (PaO2) - 15.2 (PvO2) = 5mLO2/dLblood! (in tissues)
Adipose tissue removes very little O2 from blood while skeletal muscles removes much more. What can this tell you?
Oxygen utilization by the tissues are very different! if there is a larger difference in O2 between A and V you will know that the tissue is more active
There is a consistent relationship of O2 consumed and CO2 produced. What is the relationship/ratio in glucose, fats/fattyacids, and a mix of both?
Glucose/carbs= 1:1 ratio = 1
FA/Fats: 7CO2:10O2 = 0.7
Mixed fuels: 200CO2/250O2= 0.8 (8/10) normal conditions
What is the equation for respiratory quotient (RQ) which is the ratio between CO2 produced and O2 consumed?
RQ = V(dot) CO2 / V(dot) O2
What are the three main players in carrying CO2 in the blood?
Dissolved CO2, Carbamino compounds, HCO3
CO2 has a 20x greater solubility in water/plasma compared to O2. So take 0.3 x 20 to get the solubility, which is ?
6ml CO2/dLblood/100mmHg (we will never have 100mmHg though usually much less (venous) )
Pco2 in venous blood is 45mmHg so that means that there will be?
2.7 mLCO2 dissolved in each dL of blood
CO2 binds to Hb to form carboamino compounds, however it does not bind to the heme group, instead it binds to?
the amine groups of the chains
