X-Message-Number: 5405
From:  (David L Evens)
Newsgroups: sci.cryonics
Subject: Re: Brain damage
Date: 10 Dec 1995 01:22:55 GMT
Message-ID: <4adcpf$>
References: <>

Isak Sebastian Lytting () wrote:

: Why does irreversible brain damage occur so quickly after oxygen
: supply is cut off? What exactly happens with the brain?

The structure of an active brain (at normal physiological temeprature) 
appears to need a very large amount of energy to keep it stable.  In 
fact, in a human, as much as half of all energy production may go on in 
the central nervous system.  Without oxygen, this energy production 
ceases and certain toxic materials (such as lactic acid) begin to 
accumulate as cells attempt to use anaerobic mechanisms to produce some 
energy.  The combination of a lack of energy and the production of 
additional toxins appears to both directly kill cells and cause 
small-scall damage to neurons fairly rapidly as the energy to maintain 
the highly unfavoured shape of neurons is unavailable.

Some recent work suggests that much of the mechanical brain damage that 
occurs after prolonged lack of blood flow may be caused by the stress of 
the return of circulation, but this is difficult to test and apparently 
has only recently been suggested.

--
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Ring around the neutron,   |  "OK, so he's not terribly fearsome.
A pocket full of positrons,|   But he certainly took us by surprise!"
A fission, a fusion,       +--------------------------------------------------
We all fall down!          |  "Was anybody in the Maqui working for me?"
---------------------------+--------------------------------------------------
"I'd cut down ever Law in England to get at the Devil!"
"And what man could stand up in the wind that would blow once you'd cut 
down all the laws?"
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