FUNCTIONS OF WATER
1. It is an essential constituent of all the cells of the body and the internal environment.
2. Serves as a transport medium by which most of the nutrients pass into the cells and removes excretory products.
3. Water is a medium for most biochemical reactions within the body and sometimes a reactant.
4. It is a valuable solvent in which various substances such as electrolytes, non - electrolytes, hormones, enzymes, vitamins are carried from one place to another.
5. Plays a vital role in the maintenance of body temperature. Heat is produced when food is burnt for energy. Body temperature must be kept at 80º - 108º Fahrenheit for higher or lower body temperature will cause death. Body heat is lost through the skin, lungs, urine and faeces.
6. It forms a part of fluids in body tissues; (eg) the amniotic fluid surrounds and protects the foetus during pregnancy.
7. Saliva is about 99.5 percent water. In healthy individuals it makes swallowing easier by moistening the food.
8. Water helps in maintaining the form and texture of the tissues.
9. Water is essential for the maintenance of acid base and electrolyte balance. It should be noted that pure water consists of hydrogen ion (H+) and hydroxyl ion (OH-).
Substances dissolve in water as ions with positive and negative charge. They are called electrolytes. The common electrolytes in our body are sodium, potassium and chloride.
Changes in electrolyte balance causes accumulation or depletion of water in intracellular and extra cellular fluid.
The balance between the positively and negatively charged ions is essential for water flow and maintain osmolarity between the cells. This is called electrolyte balance.
Acid base balance is the dynamic state of equilibrium of hydrogen ion concentration. When pH falls below 7 it is termed acidity and when it increases above 7 it is termed alkalinity.
Extremes of both cases results in death. The pH of the body should be maintained near neutrality. Enzymatic action depends on the pH. The digestion, absorption and utilization of nutrients are dependent on pH. Most body fluids are near neutral with the exception of gastric juice.
The pH value of some solutions are given below:
0 - Hydrochloric acid
2 - Gastric juice
3 - Vinegar, orange juice
4 - Grapes
5 - Bread, coffee
6 - Urine
7 - Pure water, eggs, blood
8 - Sea water
14 - Sodium
Water forms good source of macro minerals like Calcium, Magnesium, Fluoride, Iron and Iodine.