High Altitude Acclimatization

High Altitude Acclimatization

To the tune of “All I Want for Christmas is You” by Mariah Carey

 [Verse 1]
The use of hyperventilation
Brings alveolar PO2
Closer to inspired air
Till breaking action is induced
By central chemoreceptors
Due to a pH that’s higher
This action goes away
With the export of bicarbonate

 [Verse 2]
Next there is 6-fold increase
In lung diffusing capacity
Causing the alveolar-arterial
PO2 gradient to decrease
In the short term this is caused by
Alveolar membrane stretch
Due to increase in cardiac output
And ventilation effects

[Chorus] 
In the far more long term
The lungs will change in structure
An increase in number and size
Of capillaries and alveoli (and chest volume)

 [Verse 3]
The oxygen dissociation
Curve will have a steeper slope
Caused by a shift to the left
Which will help oxygen to load
This will be quickly corrected
By the action of the kidneys
The curve will shift back right when
Blood pH starts to decrease

 [Chorus]
And when levels of BPG
In the blood start to increase
BPG binding
Will help with oxygen unloading (in the tissues)

[Bridge] 
In the long term the renal EPO system
Causes the curve to shift upward instead
HIF is stable
Causing increased EPO
Which acts on hematopoietic stem cells
Producing more red blood cells

[Verse 4] 
Finally there is an increase
In tissue diffusing capacity
In short term this is caused by
Stretching of capillaries

 [Chorus]
But in the more long term
New blood vessels will form
In brain, heart, and muscle
But this can have pathological (consequences)

[Outro] x4
Acclimatization to high altitudes