TYPES OF BODY FLUIDS

 

INTRODUCTION: Human cells or other body fluids contain many dissolved substances known as solutes. These include; salts, sugars, acids, and bases. The concentration of solutes in a fluid creates the osmotic pressure of the solution, which in turn determines the movement of water through membranes. As an example here, we will use sodium chloride (NaCl). Human cells have an NaCl concentration of 0.9%. With human cells as a reference point, the relative NaCl concentrations of other solutions may be described with the following terms:

Isotonic: a solution with the same salt concentration

as in cells. The blood plasma is isotonic to red blood cells.

Hypotonic: a solution with a lower salt concentration

than in cells. Distilled water (0% salt) is hypotonic to human cells.

Hypertonic: a solution with a higher salt concentration

than in cells. Seawater (3% salt) is hypertonic to human cells.

When RBCs are in plasma, water moves into and out of them at equal rates, and the cells remain normal in size and water content.

If RBCs are placed in distilled water, more water will enter the cells than leave, and the cells will swell and eventually burst.

If RBCs are placed in seawater, more water will leave the cells than enter, and the cells will shrivel and die.

This knowledge of osmotic pressure is used when replacement fluids are needed for a patient who has become dehydrated. Isotonic solutions are usually used; normal saline and Ringer’s solution are examples. These will provide rehydration without causing osmotic damage to cells or extensive shifts of fluid between the blood and tissues.

RELATED;

1. RED BLOOD CELLS  

2. BLOOD PLASMA  

3. WATER

4.  IV FLUIDS

REFERENCES