- The body is composed of 50 to 75% water
	- Lean muscle contains more water (73$
	- Fat tissue contains less water (20%)
- For a healthy person, water intake equals water outtake

#  Functions
- Is a solvent
- Is a major component of blood, saliva, sweat, tears, mucus, and joint fluid
- Removes waste
- Helps transport substances
- Lubricates tissues
- Regulates body tempurature
- Helps digest foods
- Participates in many chemical reactions
- Helps maintain proper blood pH
- **Doesn't play a major role in immune system function**

# Compartments
- The body has two major fluid compartments:
	- **Intracellular water** is inside the cells - Managed by potassium and phosphorus
	- **Extracellular water** surrounds cells or is in the blood - managed by sodium and chloride
- Water **follows** sodium