Why does saline solution exist instead of pure water?

JimmyEatWorld

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Dec 12, 2000
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With regard to medical use, why do they inject a saline solution when they could just inject pure water? What about the salty nature of the liquid make a difference? Andybody? it seems like its so simple that I'm missing it

Things I thought about:
1. The Saline raises the blood pressure more than water due to its density but still remains pallatable to the human body?
2. it helps regulate the Ph balance of the blood?

Help doctors and med students
 

notfred

Lifer
Feb 12, 2001
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Cause blood is salty, so they get the solution as close to the salinity of blood as possible.
 

ElFenix

Elite Member
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Mar 20, 2000
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blood is more akin to sea water than most things
 

IcemanJer

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Mar 9, 2001
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Originally posted by: JimmyEatWorld

Things I thought about:
1. The Saline raises the blood pressure more than water due to its density but still remains pallatable to the human body?
2. it helps regulate the Ph balance of the blood?
You're right on both accounts. The pH for pure water is just slightly off of the pH of our bodies, and would cause the cells to die if pure water gets into our blood stream.
 

dethman

Lifer
Oct 12, 1999
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because blood has electrolytes. so you need to inject a solution that has a similar concentration.
 

JimmyEatWorld

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Dec 12, 2000
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Originally posted by: dethman
because blood has electrolytes. so you need to inject a solution that has a similar concentration.

oh thats right!
plus it would also stop Amino Acids, cus the membranes would be incompatible between cells.
I think.

edit: who knows why I capitalized Amino Acids :eek:
 

tcsenter

Lifer
Sep 7, 2001
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With regard to medical use, why do they inject a saline solution when they could just inject pure water? What about the salty nature of the liquid make a difference? Andybody? it seems like its so simple that I'm missing it.
Well its not "intuitive", but it is simple.

Remember Molarity, Molality, and Normality? pH is a secondary consideration.
 

Viper GTS

Lifer
Oct 13, 1999
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Causing your cells to "die" would be an understatement, they would swell up like balloons & explode.

Google on cells in a hypotonic solution, you'll see.

One link for you

Viper GTS
 

Glitchny

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Sep 4, 2002
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it exsits to make the lives of people that use contacts annoying due to the fact that the stuff isnt like water, trying to clean it up makes it seem much more like oil, practially sticks to the counter, and if it hardens its cement.. so it has multiple uses