Water in the Body

Solvent: A substance that dissolves other soluble substances to form a solution.

Solutes: Substances (e.g., sugar, salts, proteins) that dissolve in a liquid.

• If salt content in blood is too high, water moves into the bloodstream to even it out.

• If salt content in blood is too low, water leaves the bloodstream.

Water is lost through sweating, causing a loss of both water and salts.

• If not replaced, it can lead to muscle cramps, decreased energy, and weakness.

• Sports drinks and water help replenish lost fluids and electrolytes.

Water’s functions in the body:

• Transport: Moves nutrients to cells, removes waste, and transports hormones.

• Temperature regulation: Redistributes heat and cools the body via sweat.

• Lubrication: Helps with movement around sliding surfaces in the body.

• Chemical medium: Essential for chemical and metabolic reactions.

Fluids in the Body

• Intracellular fluid (inside cells) – Higher potassium concentration.

• Extracellular fluid (outside cells) – Higher sodium concentration.

  • Interstitial fluid: Found between tissue cells (80% of extracellular fluid).