Water

Physiological Functions:

• Solvent for a wide spectrum of biological compounds.
• Medium for chemical reactions.
• Medium for the transportation of digesta through the gastrointestinal tract.
• Regulation of body temperature - important properties of water:
  • High specific heat - allows for the accumulation of heat.
  • High thermal conductivity - allows for the ready transfer of heat.
  • High latent heat of vaporization - allows for the loss of large amounts of heat upon the vaporization of water (evaporative heat loss via the lungs and perspiration from sweat glands).
• Medium for the excretion of water soluble metabolic end-products (e.g., urea excretion via the urine).
• Lubricating medium for joints, organs and the central nervous system.
• Transmission of sound in the middle ear.

Sites of Absorption:

• Water absorption occurs in the jejunum, ileum, and colon (as well as the cecum of species possessing a cecum; also the ceca as in certain birds).
• In ruminant animals, net water absorption also occurs in the rumen and omasum.

Water Sources:

• Drinking water
• Moisture content of dietary foodstuffs/feedstuffs - extremely high moisture foods/feeds reduce the water needs which must be supplied via drinking water.

This page updated by G. R. Frank.