Blood Gas Transport Flashcards
What factor’s determine tissue pO2?
The rate of oxygen transport to the tissues
The rate of oxygen consumption by the tissues
pO2 in the blood/tissues can never exceed 95, why is that?
Because it is limited by the arterial blood system. THe blood leaves the lungs with the pressure and cant go above it
What’s the partial pressures of CO2 in the capillaries coming into the alveoli and leave the alveoli?
The pCO2 is 45 mmHg coming into the alveoli and it is 40 mmHg leaving the alveoli
Whats the partial pressure of oxygen in the blood coming into the alveoli through the venous system and the pressure in the blood sent out in the arteries?
PO2 is 40 mmHg in the incoming venous blood
-at 75% capacity of saturation
PO2 is 95 mmHg in the outgoing arterial blood
-at 97% saturated heme groups (not 100 because of the pulmonary shunted blood)
How much of the bloods oxygen is used up by the tissues by it return to the lungs? How much does exercise increase this?
25% (5/19.4)
Exercise: 75 - 85%
How does hemoglobin act like an oxygen buffer system in the tissues?
The pO2has to be about 40 mmHg to release the 5 ml of o/dl from the blood. If the tissue pO2 rises above 40 mmHg then it cant take up the oxygen.
When pO2 is high, oxygen binds hemoglobin
When pO2 is low (like in the tissue) oxygen release from hemoglobin.
How does pH change the saturation of hemoglobin and the partial pressure of oxygen? What’s the purpose or effect of BPG here?
A decrease in pH causes the oxy-hemoglobin curve to shift to the right, and a higher pO2 and a decrease in oxygen saturation
An increase in pH causes the curve to shift left, a lower pO2 and an increase in oxygen saturation
BPG keeps the curve slight shifted to the right
How is carbon dioxide transported in the blood?
70% transported as carbonic acid
7% dissolved in blood
The rest is bound to hemoglobin: carbamino hemoglobin
What’s the both effect and how does it effect the oxygen-hemoglobin dissociation curve?
The bohr effect is an increase in blood carbon dioxide causes oxygen to be displaced from hemoglobin.
Shifts the curve to the right
What’s the haldane effect? How does it effect the dissociation curve?
The binding of oxygen to hemoglobin displaces carbon dioxide from the blood. Hemoglobin becomes a stronger acid which gives it less of a tendency to bind carbon dioxide.
It shifts it down, more oxygen -> less co2 in the blood
Why would blood be bright red in carbon monoxide poisoning?
Carbon monoxide displaces oxygen from hemoglobin and binds 250x more strongly.
The oxygen content of. The blood is greatly reduced but the pO2 of blood may not change
What allows the diffusion capacity of oxygen during exercise?
An increased surface area of capillaries participating in diffusion
And a more almost ideal V/Q ration in the upper portion of the lungs.
How does hemoglobin acts as an oxygen buffer system for tissues?
When pO2 is high, pulmonary capillaries, oxygen binds hemoglobin
When pO2 is low, in tissue capillaries, oxygen is released
