1. Why train at high altitudes?

2. Who will feel weaker at high altitudes?
Why?
Andy Murray?
A Tibetan Sherpa?

3. Module 2: Exchange and transport
Carriage of oxygen
We are learning to…
Describe the role of haemoglobin in carrying oxygen
Explain the significance of different affinities for oxygen of fetal and adult
haemoglobin
You will be able to…
Describe and explain a dissociation curve
Compare the affinity of different respiratory pigments

4. Transport of Oxygen…
PARTIAL PRESSURE OF OXYGEN (pO2)

5. What is it?

7. Dissociation curve
Key words
•Dissociation
•Affinity
•Partial pressure
•Saturation

8. Key terms
• The partial pressure is the pressure one gas in
a mixture would exert if it were the only gas
present in the volume under discussion
• Dissociation is a general process in which
compounds separate or split into smaller
particles, ions, or radicals, usually in a reversible
manner.
• Saturation – refers to the fraction of total
protein binding sites that are occupied at any
given time

9. Oxygen transport
• Haemoglobin is made up of four subunits (2 alpha, 2 beta
haem groups) and an iron atom. There are many
specialised respiratory pigments that are able to
reversibly bind to a respiratory gas.
• 4Hb + 4O2 ↔ Hb4O8
• When an oxygen molecule binds to one subunit , it
increases the affinity of the other subunits. This
relationship is reflected in the dissociation curve.
Myoglobin is a pigment that stores oxygen in the
muscles.
• The dissociation curve is SIGMOIDAL

10. Adaptation to hypoxic environments
• At high altitudes, the air is
thinner and therefore the
partial pressure of oxygen
is comparatively lower
than closer to sea level.
• Aquatic environments also
class as hypoxic.
• To overcome these
problems, organisms have
evolved large stores of
myoglobin, and Hb with a
higher affinity for oxygen
at lower PO2

11. Fetal Haemoglobin

12. Bohr effect
• Increased carbon dioxide levels lowers the pH of the blood
• This affects the ability of the haemoglobin subunits to
transport oxygen
• A lower pH causes the
Haemoglobin to release
more oxygen
• A higher pH causes the
Haemoglobin to hold onto
more oxygen

13. Endurance training
• Exposure to hypoxic conditions can affect the Hb and
stimulate a greater release of red blood cells, thus
increasing the oxygen carrying potential of the blood.
• Increased concentration of erythropoietin
• 2, 3-DPG is an organic compound in erythrocytes that
binds with deoxy-haemoglobin
•  Reduces affinity of Hb for oxygen to enable
unloading in capillaries (shifts curve to RIGHT)