Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
How does oxygen move in the blood
|
O2 travels down a partial pressure gradient at each interface when moving from lungs to tissue
|
|
|
What two compartments in the blood hold O2
|
1. dissolved in plasma
2. bound to hemoglobin |
|
|
How should one think of Hemoglobin in regards to O2
|
As a buffer, in equilibrium with dissolved O2
|
|
|
Is O2 soluble in water
|
No, it is poorly soluble in water
|
|
|
How is the avidity in which O2 binds to Hb influenced
|
the way O2 binds to Hb is strongly influenced by the tertiary structure of the Hb molecule
|
|
|
If all hemoglobin sites are saturated what is the vol % of O2 in the blood
|
20 vol% per 100ml OR
2 vol% per 10ml |
|
|
what does 1 vol% coorelate to
|
1 ml O2 contained in 100 ml of blood
|
|
|
How is most O2 found in the blood
|
Very little O2 is dissolved in plasma, the vast majority is carried bound to hemoglobin
|
|
|
How does O2 move in and out of compartments
|
Through the dissolved form, ex: when O2 is delivered to a tissue, it is the dissolved gas that moves out.
|
|
|
What happens when O2 is delivered to a compartment
|
The dissolved gas moves out, this lowers PO2 in plasma and causes Hb to release O2--b/c Hb is a buffer.
|
|
|
How do gases dissolve and move
|
Gases move down partial pressure gradients. O2 dissociates from Hb and goes into solution in plasma, the dissolved gas then diffuses down a partial pressure gradient into interstitial space
|
|
|
How does O2 move in alveolar spaces
|
PO2 in alveolus is held at 100 by respiratory pumping. O2 diffuses down partial pressure gradient into plasma, raising PO2 in plasma. O2 associates with Hb for transport. (PO2 alveoli=40)
|
|
|
what determines the concentration of O2
|
determined by PO2 (partial pressure of O2), which determines the number of O2 molecules that are dissolved in the plasma
|
|
|
Is CO2 transported in the blood the same way as O2
|
No, transported differently. CO2 is transported in 3 ways:
dissolved in plasma (H2CO3) as bicarbonate (HCO3) bound to Hb (HbCO2) |
|
|
What is a carbamino
|
HbCO2
|
|
|
What is the solubility of O2 in water
|
.003 vol%
|
|
|
what is the solubility of CO2 in water
|
.06 vol%
|
|
|
what is the PCO2
|
40 torr
|
|
|
What does it mean in the physiological sense that CO2 is 20X's more soluble in blood than O2
|
20 X's more CO2 is carried in the dissolved form than O2
|
|
|
What catalyzes the reaction of CO2 and H2O in the RBC
|
carbonic anhydrase
|
|
|
what buffers the H+
|
hemoglobin
|
|
|
how does the bicarbonate ion leave the RBC
|
it diffuses down its concentration gradient out of the RBC. It is replaced by an inward flux of Cl- ions.
|
|
|
About how much CO2 is transported as bicarbonate
|
85%
|
|
|
Why does the enzymatic reaction of CO2 and water take place in systemic capillaries
|
b/c Hb is deoxygenated and therefore available to buffer H+ ions
|
|
|
How does the enzymatic exchange of CO2 occur in the lungs
|
in the lungs, the process is repeated in reverse. Hb gains O2, which displaces H+. This drives the reaction of H+ and HCO3- back to the H2O & CO2 direction. The CO2 leaves the RBC's and capillaries by diffusion
|
|
|
How can CO2 enter RBC readily
|
it is lipid soluble
|
|
|
where is carbonic anhydrase found and where are H+ ions generated
|
inside the RBC (both).
H+ ions being generated in the RBC is a good place because it is buffered by Hb which is also found in the RBC...buffering by Hb minimizes the resulting change in H+ion concentration |
|
|
How are carbaminos formed and does Hb have a high affinity for CO2
|
CO2 reacts with deoxygenated Hb to form carbamino compounds. It is a fast reaction. Hb has a low affinity for CO2
|
|
|
How much CO2 is transported as carbamino compounds
|
5-10%
|
|
|
What is the relationship between PCO2 and CO2 content of blood
|
it is a linear curve and does not show any saturation
|
|
|
What are some things that effect Hb's affinity for O2
|
H+ ion concentration-increasing H+ ions concentration lowers Hb affinity for O2
Temp-increasing temp lowers affinity for O2 PCO2-at high PCO2, HBCO2 is higher thus reducing # of Hb sites available for O2 binding certain diseases- carbon monoxide poisoning. CO binding to Hb dramatically increases teh affinity of Hb for O2 |
