Question

6. Explain why the remedy to sever dehydration is not intravenous administration of water. Instead, saline solution (a solution that is isotonic to the liquid inside your cells) must be used for this purpose. Your description must include the terms cell membrane, semi-permeability, diffusion and osmosis. Simple listing of definitions of these terms will not receive credit (5 points)

Answer 1

Definition :-

• A saline solution is one consisting of a salt such as sodium chloride (common table salt, NaCl) dissolved in water.

• Saline solutions are often used by emergency personnel to give fluids intravenously (from a bag through a needle in your arm, for example) and to give gastric lavage when a poison has been ingested.

• A more common everyday use of saline is for the rinsing of contact lenses.

It is used is to maintain a balance of osmotic pressure between the body's cells and fluids.

Cell membranes are selectively permeable which, in this case, means that water can enter and leave the cell freely but most species in solution cannot. Two systems separated by a selectively permeable membrane like this will seek an equilibrium, with water moving however it has to in order to make both systems roughly equally concentrated.

The body is in a state of dehydration when fluid levels drop to a point at which organs and bodily functions, such as circulation and respiration, can’t function normally. It occurs when the body loses more fluids than it takes in.

One can usually remedy mild dehydration by drinking water or drinks packed with electrolytes.

If someone don’t notice the early signs of dehydration or don’t rehydrate soon enough, then can move from being mildly to severely dehydrated.

Normal saline (0.9% sodium chloride solution) is isotonic, meaning it has the same concentration of sodium and other solutes as body fluids. Since water moves an area of lower concentration to an area of higher concentration , an infusion of normal saline will not result in changes in fluid movement into or out of bloodstream and cells.

Water is hypotonic, meaning the concentration of dissolved solutes is less than that of your body fluids and cells.The effect of infusion of water would be to cause water movement out of circulation and into cells. If cells are not dehydrated ,this would cause them to swell , even burst. IV solutions those used : D5W (5% dextrose in water) for treatment of dehydration as well as low blood sugar.

Using more concentrated solutions (hypertonic) would draw water out from the cells and result in them being dessicated.