Gas Transport by blood Flashcards
What is the most abundant gas in the atmosphere?
Nitrogen
What are the 2 gases that participate in gas exchange?
Oxygen and CO2
What is the sum of all the partial pressures at sea level?
760 mmHg
Calculate the partial pressure of Oxygen (Pp)
% of composition x P total
21% x 760 mmHg
160 mmHg
What is the % Nitrogen in the atm?
78%
What states that the total pressure exerted by the mixture of gases is equal to the sum of the partial pressures of the gases in the mixture?
Dalton’s law
What happens to gas in high altitudes?
It becomes less dense (pressure decreases)
Which partial difference is greater at capillaries, oxygen or co2?
Oxygen’s (23 mmHg of difference vs 1 of co2)
T/F: gas composition changes as you increase altitude
False
What does Henry’s Law state
@ constant temp: amount of gas dissolving in a liquid is proportional to the partial pressure of that gas
At 1 mmHg of PaO2, how much O2 is dissolved in 100 ml of blood?
0.003ml of O2
If gas pressure increases, what happens to solubility?
Increases
What percentage of Oxygen is bound to Hemoglobin?
97%
Which molecules represent the partial pressure of O2?
Those dissolved in plasma (not bound to hb)
T/F Oxygen bound to Hb will exert pressure
False
What value is used to know how much oxygen is bound to Hb?
Saturation (SaO2) in arterial blood
What is the red pigment in hemoglobin called?
Heme
How many molecules of Oxygen does each Hb combine with?
4
What type of curve is the oxyhemoglobin dissociation curve?
Sigmoidal
Hg behavior depends on?
PO2 - affinity for heme group depends on oxygenation of others
SvO2 is around?
75%
What happens to SaO2 if PaO2 increases?
Does not change
When do the SaO2 curve go into a steep curve?
When PaO2 is <60 mmHg
What value of PaO2 is p50?
27 mmHg
Define p50
PaO2 pressure at which 50% of Hb is saturated
If there is a right shift in the OxyHg-Dissociation curve, what does it mean?
Decreased o2 affinity
Metabolic alkalosis, hypothermia, and low PaCo2 can lead to a shift in the curve in which direction?
Left
Metabolic acidosis will increase or decrease the p50?
Increase
What are 2 ways Oxygen is transported in a pathological manner?
Methemoglobin
CO Hb
Fe 2+ gets oxidized into Fe3+ in methemoglobin. What can you used to treat this?
Methylene blue
What happen in COHb transport?
O2 and CO2 bind in the same site and compete for each other
CoHb transport will provide a shift to the curve to what side?
left
Define Hufner’s constant
1g of Hb can combine 1.34 ml O2
How many ml of O2 can 15g Hb/dl hold?
20.8 ml
What does CO2 react with to produce Bicarbonate?
water
How many mls of CO2 are transported in 100 ml of blood?
4 ml
Is Co2 mostly transported with water in arterial or venous blood ?
Arterial blood
List the 3 ways Co2 can be transported
- Dissolved
- Reacting with H2O
- Combining with proteins
