• Carries nutrients and waste in the body
• Maintains structure of molecules: proteins, glycogen, etc...
• Participates in chemical reactions in the body
• Acts as a solvent for most nutrients
• Lubrication and cushioning of joints, spinal cord, and fetus (during pregnancy)
• Helps regulate body temperature
• Maintains blood volume

Terms:

Intracellular fluid: fluid within the cells

Interstitial fluid: fluid between cells (component of extracellular fluid)

Extracellular fluid: fluid outside of the cells

• includes interstitial fluid, plasma, and the water in skins and bones
• accounts for 1/3 of the body's water

Hydration

Dehydration occurs when water output exceeds water input.  Signs of dehydration include dry skin, dry mucous membranes, rapid heartbeat, low blood pressure, and weakness.

Water intoxication refers to the rare condition when body water contents are too high.

Sources:

• water - 100%
• fruits and vegetables - 90-99%
• fruit juices - 80-89%
• pasta, legumes, beef, dairy - 10-60%
• crackers, cereals - 1-9%
• oil - 0 %

Amount needed:  a 2,000 kcalorie (average) energy expenditure person requires about 2-3 liters (7-11 cups) per day.