Oxygen dissociation curve Flashcards
at a very low concentration of oxygen what are the 4 polypeptide chains of the haemoglobin molecule like?
closely united
so it is difficult to absorb the first oxygen molecule
once the first oxygen molecule is loaded what does it cause the other polypeptides to do?
load the remaining three molecules very easily
why does the graph tail off at very high oxygen concentration?
the haemoglobin is almost saturated with oxygen
what does it mean if the oxygen curve is further to the left?
the greater the affinity of haemoglobin for oxygen
what does it mean if the curve is further to the right?
the lower the affinity of haemoglobin for oxygen
what happens to haemoglobins affinity for oxygen in the presence of carbon dioxide?
it is reduced
at a gas exchange surface what is the carbon dioxide concentration like and what effect does that have on the haemoglobin?
the c02 level is low so the affinity of haemoglobin for oxygen is increased.
That along with the high concentration of oxygen means the oxygen is readily loaded
and the curve has shifted to the left
what is the carbon dioxide level like in respiring tissues and what effect does it have on the haemoglobin?
level of C02 is high, the affinity for oxygen is reduced
coupled with low conc of oxygen, the oxygen is readily unloaded from the haemoglobin into the muscle cells
the curve has shifted to the right
why does carbon dioxide cause haemoglobin to more readily release oxygen?
dissolved carbon dioxide is more acidic and the low PH causes haemoglobin to change shape
what is happening at the gas exchange surface?
carbon dioxide is constantly being removed
what is the PH like at the gas exchange surface?
the PH is raised due to low levels of CO2
what does the raise in PH in the gas exchange surface do to the haemoglobin?
the higher PH changes the shape of the haemoglobin into one that enables it to load o2 readily
this increases the affinity of oxygen- it is not released while being transported in the blood
the more active the tissue….
the more oxygen is unloaded
where does haemoglobin become saturated with oxygen?
in the lungs
how many oxygen molecules are released at a tissue with low respiring rate?
one molecule
