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To: flaglady47
"Well, helloooo, this is after she was being dehydrated for two weeks. The brain is 80% water, so naturally during the extended process of dehydration, it would lose water and weight."

Mild dehydration... The autonomic nervous system causes the vessels in the brain to ***become dilated to keep more blood in the brain*** while vessels in the rest of our body become constricted to keep our blood pressure up. The pressure from the dilated vessels puts pressure on the
brain (because it's encased in the skull) and we get a headache.

Luckily, there are many compensatory mechanisms in place to protect the brain above all other body parts. Groups of cells in the aorta and in the hypothalamus work to sense the fluid volume and the osmolarity (how concentrated or dilute the blood is) and orchestrate hormonal signals to ***compensate for the loss of water.***

You can find this information in a basic physiology book ( one by Lauralee Sherwood) and many neuroscience texts in your library.
http://www.madsci.org/posts/archives/sep99/938556195.Ns.r.html

Dehydration...
When we become hypovolemic several things happen. First our heart speeds up. It pumps less volume per beat (stroke volume) but beats more often to compensate for this and maintain cardiac output (the number of liters of blood pumped per minute). Second the blood levels of catecholamines (epinephrine, norepinephrine and dopamine) go up. ***This causes blood vessels in the critical organs such as heart, brain, liver and kidneys to dilate*** and the vessels in the less critical areas (gut, muscles) to constrict. Changes in the output from our sympathetic nervous system reinforce this. ***The net effect is reduced blood flow to the muscles and gut and more to the brain etc.*** Thirdly, receptors that measure our blood pressure, our sodium level, etc. tell the brain to increase our volume, this kicks in our thirst mechanism. Fourthly, the atria of our heart, since they are smaller in diameter reduce their production of ANP, a peptide hormone that stimulates the kidneys to make urine. Thus the kidneys reduce their secretion of sodium and urine.
Robert S. Joseph, RPh, MD, FCCP
Board Certified Internal Medicine and Critical Care Medicine

In other words, the brain weight loss would be minimal. Please feel free to select a bulb.
50 posted on 06/16/2005 4:31:07 AM PDT by Smartaleck
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To: Smartaleck; flaglady47; evad

Thanks evad for poiting me to search on "hypernatremic dehydration".

And for Smartaleck and flaglady: personal insult and quoting irrelevant material reflects badly on you, not me.

You only quoted what happend in initial dehydration, NOT what happens,when someone actually dies of it.


"When hypernatremic dehydration occurs, the brain shrinks. Tears of the communicating vessels and hemorrhage may occur. To compensate, the brain produces "idiogenic osmoles" (aspartate, glutamate, taurine) which raise the tonicity of the brain cells and limit shrinkage. "



http://64.233.187.104/search?q=cache:S--63O4dSpcJ:gucfm.georgetown.edu/welchjj/netscut/fen/hypernatremic_dehydration.html+Hypernatremic+Dehydration+shrinkage+brain&hl=en&ie=UTF-8


"Acute hypernatremia often results in significant brain shrinkage, thus causing mechanical traction of cerebral vasculature."


http://www.emedicine.com/emerg/topic263.htm


80 posted on 06/16/2005 6:56:33 AM PDT by FairOpinion
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To: Smartaleck

I'm just a layman on the human body, I readilly admit. But if you love someone, and you are told by that loved one's family memebers that she talked, and they play the tape, and they show you videos of her appearing to respond, what would you expect the judge to do? Would you honestly expect the judge to ignore all that?

Frankly, I don't even need to prove that she could have recovered. The burden of proof lies on the executioner.


98 posted on 06/16/2005 8:06:43 AM PDT by Arthur Wildfire! March (SICK TURBAN DURBIN THE VERMIN)
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To: Smartaleck

In other words, the brain weight loss would be minimal. Please feel free to select a bulb.

See autopsy for actual facts, not that which you wish to believe. Just stepped on your bulb. Was a defective one.


142 posted on 06/16/2005 12:48:15 PM PDT by flaglady47
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To: Smartaleck

You forgot to include the first part of your cited text:

"The body attempts to maintain the levels of nutrients, ions, and gases at constant levels appropriate for the functioning of the body (homeostasis). Severe dehydration can have adverse affects on the brain such as cell
death and seizures which can lead to increased cell death in the brain. This may be due to a change in the ionic composition of the fluid surrounding brain cells (neurons) which causes neurons to be more 'active'than usual and more sensitive to stimuli."


214 posted on 06/17/2005 10:57:06 AM PDT by kpmom
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