Term
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Definition
| total pressure of a mixture of gasses is the sum of the pressures of individual gases (sum of the partial pressures) |
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Term
atmosphermic pressure * % O2
at sea level this would be 760mmHg * 21% (0.21) = 160 mmHg
In a person with 100% oxygen this would be 760 * 1 = 760 mmHg
fun facts: CO2 = 0.3%, Nitrogen is 76-78% |
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Definition
| partial pressure of O2 in the air (equation) |
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Term
| the partial pressure of that gas in equilibrium with that liquid |
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Definition
| According to Henry's law, at constant temperature the amount of a given gas dissolvd in a given type and volume of liquid is directly proportional to what? |
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Term
| Henry's law O2 dissolved = solubility * PO2 |
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Definition
| the concentration of O2 dissolved in water is proportional to the PO2 in gas phase is an example of what law? how do you calculate the O2 dissolved? |
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Term
| less, O2's solubility sucks it is 27 times less than CO2 |
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Definition
| the solubility of oxygen is greater than or less than CO2? |
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Term
| DO NOT! solubility is different for different gases!!!! |
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Definition
| equal partial pressure (do/do not) mean equal concentration |
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Term
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Definition
| what is the solubility of O2 in plasma? |
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Term
1) dry atmospheric air is humidified (reducing partial presure of O2)
2) CO2 diffuses from the pulmonary blood into the alveoli(reducing partial pressure of O2)
3) alveolar air is only partially replenished every breath with atmospheric air
4) oxygen is constantly absorbed into the pulmonary blood from the alveoli |
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Definition
| Why is the partial pressure in the alveoli not equal to the atmostpheric partial pressure of oxygen? |
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Term
| atmospheric: 160mmHg (760 * .21) alveolar: 100mmHg FiO2 *(Patm -PH20) -(PaCO2/RQ) .21 *(760-47)-(~40/0.8) = ~100 |
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Definition
| what is atmospheric PO2? alveolar? |
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Term
| fraction of inspired oxygen |
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Definition
| What does FiO2 stand for? |
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Term
| respiratory quotient, ratio of total CO2 production to O2 consumption, typically around 0.8 (or you can multiply by 1.25 to make it easier) |
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Definition
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Term
| carbs = 1.0, lipids = 0.7, proteins = 0.8, normally people are burning a combination of lipids and carbs |
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Definition
| why is respiratory quotient usually 0.8? |
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Term
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Definition
| what does increasing alveolar partial pressure of CO2 do to PAO2? |
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Term
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Definition
| gases move from __ concentration to ___ concentration |
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Term
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Definition
| ideally, alveolar PO2 should equal arterial PO2, when compared what is this known as? |
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Term
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Definition
| what factors can decrease alveolar PO2? |
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Term
pressure, surface area, diffusion coefficient, membrane thickness, membran resistance
all part of Fick's law of diffusion |
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Definition
| what things can alter diffusion rate? |
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Term
diffusion rate is proportional to:
(change in pressure * SA * diff. coefficient)/(membrane thicknes * membrane resistance) |
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Definition
| what is Fick's law of diffusion? |
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Term
COPD/emphysema decreases surface area
Pulmonary Edema increases membrane thickness(diffusion distance)
Pulmonary fibrosis increases membrane thickness |
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Definition
| how does COPD or emphysema decrease diffusion? Pulmonary edema? Pulmonary fibrosis? |
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Term
1/3 = normal
1/2 = with diffusion problem
there is plenty of time for O2 to diffuse at rest in either state
diffusion is not a limiting factor |
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Definition
| At REST typically at what distance along the capillary is all of the oxygen diffused from the alveoli? with a diffusion problem? |
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Term
normal: about 75% of the way
diseased: can go the whole length of the capillary without full diffusion
diffusion is limiting in the diseased state during excercise as there is not enough time for the oxygen to diffuse where it needs to. |
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Definition
| with EXCERCISE(say 3 x cardiac output) how far down the capillary is all of the O2 diffused normally? with a diffusion problem? |
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Term
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Definition
| how far down the capillary does it take CO2 to diffuse in a normal person? |
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Term
| there is a lower change in pressure (delta P) basically the CO2 goes from 46 to 40mmHg and the O2 is going from 40 to 100mmHg |
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Definition
| if CO2 is more soluble that oxygen, why does it take about the same amount of time for it to diffuse? |
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Term
basically, what causes the A-a gradient?
most causes of hypoxia (except for hypoventilation) |
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Definition
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Term
altitude will change PO2 overall (decreases both alveolar and arterial equally, so no A-a change)
hypoventilation does not change A-a
increased thickness of lungs allows the alveoli to become ventilated (increased Palv) while the arterial PO2 decreased because the O2 can't get to the blood as easy-this increases the A-a gradient
Edema will also raise the A-a gradient because again it is harder to get the O2 to the blood so arterial blood will decrease in O2 while alveolar is the same or higher. |
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Definition
explain which of these 4 things will alter A-a gradient and why?
1) high altitude
2)hypoventilation
3)increased thickness of lung
4)edema |
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Term
| alveolar ventilation - arterial PaO2 (from the arterial blood gas lab test) |
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Definition
| how do you calculate the A-a gradient? |
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Term
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Definition
| what is a normal A-a gradient in a healthy individual? |
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Term
diagnosing causes of hypoxemia
(according to Gaddis: hypoventilation, V/Q mismatch, diffusion issues, Shunt) |
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Definition
| what does the A-a gradient help with? |
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Term
V/q mismatch
widens A-a gradient
causes hypoxia |
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Definition
| if a patient does not have a history of diffusion issues, what could be to blame? what does this do to A-a gradient? to the patient? |
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Term
dissolved in plasma OR
bound to Hemoglobin
PaO2 measures the plasma partial pressure |
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Definition
| how is oxygen transported in the blood? what does PaO2 measure? |
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Term
| no! the A-a gradient doesn't have to do with O2 bound to hemoglobin, just plasma. Decreased RBC's will not affect it. |
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Definition
| does Anemia alter the A-a gradient? why? |
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Term
| plasma <2%, 0.3 mL/dL Hb >98% 19.7 mL/dL total is 20 mL/dL |
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Definition
| how many mL/dL of blood is O2 dissolved in arterial blood plasma? bound to Hb? what are the percents? what is the total PO2 in blood? |
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Term
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Definition
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Term
each iron binds 1, so 4 total
also remember the 2 alpha, 2 beta subunit business |
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Definition
| how many O2 can each iron bind on hemoglobin molecules? how many is that total per Hb molecule? |
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Term
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Definition
| what color is hemoglobin when it is not bound to O2? |
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Term
| conformational changes that assist loading of oxygen |
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Definition
| how does binding of 3 O2 molecules increase the binding of the 4th to hemoglobin? |
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Term
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Definition
| does de-oxy hemoglobin have a higher affinity for O2 or CO2? |
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Term
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Definition
| how much Hb/dL blood does a person normally have? |
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Term
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Definition
| how many mL O2 can 1 g of Hemoglobin bind? |
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Term
| if all Hb are fully loaded 15g/dL * 1.35 mL O2/g = 20.1 mL O2/dL |
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Definition
| if you have 15 g of hemoglobin with the ability to bind 1.35 mL O2, what is your oxygen carrying capacity? |
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Term
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Definition
what's the dissociation curve of oxyhemoglobin look like?
what shifts this curve, and in what directions? |
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Term
| pressure at which Hb is 50% saturated (usually around PO2 = 27 mmHg) |
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Definition
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Term
resting cell: 40 mmHg at 75%
alveoli: 100 mmHg at 97% |
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Definition
| what is PO2 of a resting cell & its percent O2 saturation of Hb? how about alveoli? |
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Term
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Definition
| increasing PO2 increases dissolved O2, what law accounts for this? |
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Term
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Definition
| what is O2 carrying capacity for arterial plasma? |
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Term
| venous: 75% + excercise: 30% (lower because excercising tissue needs to unload O2) arterial: 97% |
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Definition
| what is the 02 saturation of venous blood? with excercise? arterial blood? |
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Term
| carrying capacity of oxygen, ~20 mL/dL |
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Definition
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Term
| 15.3 mL O2 = .75 * (20mL/dL) |
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Definition
| what is the O2 carrying capacity of venous plasma? |
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Term
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Definition
| how much O2 does your body extract from blood during resting conditions? |
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Term
5 mL/min (250/4.7)
250 is amount consumed, 4.7 = amount used at rest
plasma would be like 250/.3 so 83 L/min or something crazy |
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Definition
| if normal O2 consumption at rest is 250 mL O2/min, what is cardiac output to satisfy this? what would it be if this were plasma O2? |
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Term
| percent saturation of hemoglobin with oxygen (y axis of O2 sat curve) |
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Definition
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Term
| total oxygen content of mixed venous blood |
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Definition
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Term
composition of air, alveolar ventilation, & efficiency of gas exchange
amount of Hb-# of Hb molecules, number of functional RBC's, blood volume
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Definition
| what is amount of O2 bound to hemoglobin determined by? what is the amount of hemoglobin determined by? |
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Term
| Hematocrit normal is 40-50% |
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Definition
ratio of red blood cells to plasma.
what is the normal range of this? |
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Term
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Definition
| decrease in hemoglobin and thus a decrease in O2 carrying capacity of the blood |
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Term
| polycythemia - RBC's plug up capillaries |
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Definition
| increased above normal amounts of RBC's hematocrit concentration is 60-70% |
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Term
erythropoietin
released by kidneys in response to low oxygen levels (hypoxia) |
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Definition
glycoprotein that increases # of RBC's
what is it?
where is it released?
what triggers it's release? |
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Term
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Definition
| low tissue oxygenation -> Erythropoietin -> hemopoeitic stem cells -> ________ -> RBC -> increased tissue oxygenation |
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Term
| go to high altitude, make a bunch more RBC's and you can carry more O2 |
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Definition
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Term
| increased CO2, increased H+ (decreased pH), increased DPG, and increased temperature this would occur when a person is exercising so the O2 can unload better |
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Definition
| what causes a "right shift" and in what conditions would this occur? |
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Term
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Definition
| what causes a left shift of the oxy hemoglobin dissociation curve? |
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Term
| Bohr effect-changes in pH, PCO2, and temp can alter binding affinity for O2 |
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Definition
| increased H+ causes a rightward shift, good for unloading O2 |
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Term
| it makes it harder, hypoxia stimulates DPG production which creates a right shift |
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Definition
| does a left shift make it harder or easier to unload O2 from blood? what could cause this? |
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Term
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Definition
| what has a 200x greater affinity for hemoglobin that O2? |
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Term
| O2 saturation looks normal because O2 is bound to Hb, it just cannot unload, therefore tissue O2 will be low |
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Definition
| with CO poisoning, what happens to SaO2? tissue O2 level? |
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Term
1) dissolved in plasma ~7%
2) bound to Hb(carbamino Hb) ~23%
3) in the form of bicarbonate (HCO3-) 70% |
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Definition
| name the 3 ways CO2 is carried in the blood |
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Term
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Definition
| allows CO2 to travel in the blood and acts as a buffer system |
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Term
| carbonic anhydrase in the RBC! |
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Definition
| how does CO2 and water make bicarb? |
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Term
| some kind of Chloride ion exchange deal |
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Definition
| how is bicarb transported out the RBC when it is made? |
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Term
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Definition
| what else binds to hemoglobin besides O2, CO, and CO2? |
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Term
it is steeper, 6/4 vs 60/4.7
it is not sigmoidal, its more linear |
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Definition
| how does the CO2 dissociation curve differ from the O2 curve? |
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Term
| Deoxygenation of the blood increases its ability to carry carbon dioxide. Conversely, oxygenated blood has a reduced capacity for carbon dioxide. |
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Definition
| what is the Haldane effect? |
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