Flashcards in *Physiology 4 (lecture 5) Deck (14)
What are the possible means of CO2 transport in the blood?
In solution (10%)
As bicarbonate (60%)
As carbamino compounds (30%)
The amount of a given gas dissolved in a given type of liquid (e.g. blood) at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid
(this means that if the partial pressure in the gas phase is increased, the concentration of the gas in the liquid phase would increase proportionally)
What is the partial pressure of a gas in solution?
Its partial pressure in the gas mixture with which it is in equilibrium
What is more soluble, O2 or CO2?
CO2 is about 20 times more soluble than O2
What is the equation for bicarbonate?
CO2 + H20 H2CO3 H+ + HCO3-
What enzyme catalyses the addition of Co2 and H20 to form H2CO3?
Where does this occur?
Carbonic anhydrase (CA) - occurs in RBCs
Where does the H+ from the breakdown of H2CO3 go?
Binds to haemoglobin forming HbH
ho ware carbamino compounds formed?
How quick is this reaction?
By the combination of CO2 with the terminal amine groups in blood proteins (especially global of haemoglobin to form carbamino-haemoglobin)
Rapid, even without an enzyme
Can a reduced Hb bind more or less CO2 than HbO2?
What is the Haladane effect?
Removing O2 from Hb increases the ability of Hb to pick up CO2 and CO2 generated H+
What is the Bohr effect?
the influence exerted by carbon dioxide on the oxygen dissociation curve of blood, that is, the curve is shifted to the right, which means an apparent reduction in the affinity of hemoglobin for oxygen.
What 2 effects work in synchrony to facilitate O2 iteration and uptake of CO2 and CO2 generated H+ at tissues?
The Bohr and the haladane effect
what is the purpose of the Bohr effect?
to facilitate the removal f O2 from haemoglobin at tissue level by shifting the O2-Hb dissociation curve to the right