Human Nutrition 3(3+0)

Lesson 45 : Water Functions and Water Balance

Water Balance

Water balance refers to the balance between the amount of water consumed and the amount of water excreted. For optimal functioning of the body, it is essential that the water content of the body should be maintained constant. Body fluids contain solutes (chemical compounds that are soluble in water), which separate into charged particles, or ions, when dissolved in water. Intracellular fluids are high in potassium and phosphate ions, while interstitial fluids are high in sodium and chloride ions. These ions help to maintain the amount of fluids both within and outside the cells. Water molecules follow the solutes moving across cell membranes from a lower to higher solute concentration to maintain homeostasis.