PHYS20008 Lecture Notes - Lecture 22: Ph, Homeostasis, Anemia
12 Jun 2018
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Lecture 22
PHYS20008 - HUMAN PHYSIOLOGY
LECTURE 22
RESPIRATORY CHALLENGES
CHANGES IN HAEMOGLOBIN’S AFFINITY FOR O2
•A small decrease in arterial PO2 will have a little effect on Hb affinity for O2.
•During exercise, the PO2 of the tissues (systemic capillaries) decrease to approx, 25 mmHg. This
dissociates large amounts of O2 from Hb.
•1. Oxygen-Haemoglobin dissociation curve shift to right:
•Different conditioned cause the curve to shift.
•The more acidic something gets, the curve shifts to
the right (pH).
•As things get hotter, things shift to the right and
Hb will dole out more O to that particular tissue.
•More CO2 in a particular environment, the more
generous Hb will be when giving out the O.
Lecture 22
PHYS20008 - HUMAN PHYSIOLOGY
•2. Oxygen-Haemoglobin dissociation curve shift back to original
position:
EFFECT OF 2, 3-DPG IN RBCs
•2,3-DPG is a compound made from an intermediate of the
glycolysis pathway (byproduct of anaerobic metabolism).
•This environment would be deprived of oxygen, so we want
something to be there to cause Hb to be more generous to
donate it’s O. 2, 3-DPG does this.
•It can affect the curve above. Causes a shift to the right.
•Increase in 2,3-DPG in Red Blood Cells due
to Low O2.
•Chronic Hypoxia/High Altitude/
Anaemia.
•The
difference
between
the other
factors
above and
2, 3-DPG
is that 2,
3-DPG
actually
binds to the RBCs themselves
rather than just being local to the
environment.
•So it is still there in the RBCs even
once they get back to the lungs.
•Two components of O in the
blood are O dissolved in plasma,
and O bound to Hb.
•O diffusion between alveoli and
blood depends on SA and
diffusion distance.
OXYGEN CONTENT OF
ARTERIAL BLOOD
•Flow chart above.
CO2 TRANSPORT IN BLOOD
•Moves around the body same as
O. More soluble, so higher % of
CO2 can be dissolved in plasma
itself (7%).
•Can bind directly to Hb. 23%
transported this way.
•Majority transported as
bicarbonate (HCO3-) and H ions.
Document Summary
Changes in haemoglobin"s affinity for o2: a small decrease in arterial po2 will have a little effect on hb affinity for o2, during exercise, the po2 of the tissues (systemic capillaries) decrease to approx, 25 mmhg. This dissociates large amounts of o2 from hb: 1. Oxygen-haemoglobin dissociation curve shift to right: different conditioned cause the curve to shift, the more acidic something gets, the curve shifts to the right (ph), as things get hotter, things shift to the right and. Hb will dole out more o to that particular tissue: more co2 in a particular environment, the more generous hb will be when giving out the o. Oxygen-haemoglobin dissociation curve shift back to original position: 2, 3-dpg does this: it can affect the curve above. Causes a shift to the right: increase in 2,3-dpg in red. Blood cells due to low o2: chronic hypoxia/high. Anaemia: the difference between the other factors above and.
