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Re: Where is potassium found?
Sean Stinson (sstinson@uoguelph.ca)
27 Oct 1995 16:50:16 GMT
Phillip Bigelow (n8010095@cc.wwu.edu) wrote:
: >Is there any reason why potassium would be secreted?
:
: Yes, too much potassium in Primates' hearts will stop the heart.
: During open-heart surgery, cardiologists will inject potassium chloride into
: the heart to stop it from beating.
Sean replied,
now your in my territory. This an oversimplification.
The body tries to maintain a gradient of K+. Intracellular
K+ is around 150 mM and extracellular K+ is around 4 mM.
This is required by all cells to maintain cell function and
is a major source of energy consumption. The Na-K+ ATPase (pump)
brings K+ into the cell and take Na out. It would be very
unlikely that the body would ever die of high [K+] the kidney
functions would have to be so impaired that we would die of nitrogen
toxicity first. As well the cells of the body would increase
the intracellular concentrations of K+, thus eliminating
the increase in K+, assuming the animal could ingest and absorb
this high concentration of K+ in the first place. So
the comparison to heart surgeons is invalid as it refers
to a non-environmental condition. The heart stops if
you inject cyanide into it too. This doesn't make cyanide
excretion an important factor in this discussion. While
the body does excrete pottasium, I don't believe this
is an important aspect of AAT. Other terrestrial animals
excrete about the same amounts of K+ as humans. Comparing
the renal capacity of humans to aquitic mammals is like
saying anti-AAT is right. You might try arguing
that humans have a slightly higher renal capacity to other
terrestrial mammals. I don't know the relavent data on this.
I'll see if I can get some numbers on this aspect.
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