high altitude oxygen dissociation curve

[strive01]

i was wondering the effect of high altitude on the oxygen dissociation curve? i think the reason I am not understanding this is because i always get confused with the effect of partial pressure of o2 on the dissociation curve.. i feel like its just the more pressure of o2, the greater hemoglobin is saturated with oxygen.. correct? no? ah.

---

Members don't see this ad.

 

[crevmed]

The graph is Hg saturation vs partial pressure of Oxygen. With increase altitude the partial pressure of O2 is lowered therefore the Hg saturation is lowered. This is a movement down the curve and not a shift of the curve. The curve shifts beacause of changes in pH, BPG, Temp and Partial Pressure of CO2.

 

[TheBeardedClam]

An easy mnemonic for the disassociation curve is:


Right
If
BPG ^
[H+] ^
Temp ^

So, essentially, if you have an increase in temp, hydronium ion concentration (think increase in CO2), or an increase in BPG binding/concentration the curve will shift to the right. Everything else shifts it to the left.

 

[strive1]

I believe there is a shift. I don't remember which one it is though...

P.s> wow we have really simliar names!

 

[CaptainSSO]

This will never be on the MCAT.

But yea crevmed is correct, it would shift down.

Edit: I actually just posted this to see how my new avatar looks. Unfortunately I can't make it any bigger. :[

 

[NYR56]

Try making it less wide (crop some green), it should increase in height then.

BTW, this thread is from last year. High altitude also increases the release of BPG, which shifts the curve, but yeah, this is getting into too much depth.

 

[SN2ed]

Thread moved to Study Question Q&A. These types of questions belong in this forum.

 

[CaptainSSO]

Try making it less wide (crop some green), it should increase in height then.

BTW, this thread is from last year. High altitude also increases the release of BPG, which shifts the curve, but yeah, this is getting into too much depth.

Ah, much better. Thanks.

 

[traitorman]

but animals who are accustomed to high altitudes have a left shift looking curve i believe.

less 02 availability = more 02 saturation at a lower concentration

 

[traitorman]

had a question like this on one of my kaplan FL

 

[strive1]

but animals who are accustomed to high altitudes have a left shift looking curve i believe.

less 02 availability = more 02 saturation at a lower concentration

that makes sense. so shift to the left. not right.

 

[UCB05]

Yay for old threads.

Going from low elevation to high elevation does nothing to the dissociation curve. What happens is that since the partial pressure of O2 is lower at higher elevation, a person occupies a lower pO2 point on the curve (which hasn't changed), which indicates a lower level of O2 saturation. Later, there are acute and chronic effects due to oxygen deprivation that causes a shift to the RIGHT. This is adaptive so that in the new equilibrium, such as in animals acclimated to the high altitude, the oxygenated Hb saturation is lower than at sea level, but the drop in pressure in the tissues results in a greater amount of O2 dumped.

Remember it's not the actual % saturation that matters, but the change in % saturation across a pressure difference. A shift to the right, especially when working in the cooperativity range, results in a larger % sat difference. A shift to the left implies increased Hb affinity for O2 at all pressures, which is a nono because it means O2 doesn't leave Hb when it's supposed to and tissues starve.

 

[thejaundice]

It is left-shifted.

At least it is in animals living in high altitudes.