Saliva
From Freepedia
- For the band, see Saliva (band).
Contents of Saliva
In animals, saliva is produced in and secreted from the salivary glands. It is a fluid containing:
- water
- electrolytes
- mucus Mucus in saliva mainly consists of mucopolysaccharides and glycoproteins.
- and various enzymes. The major enzymes found in human saliva are alpha-amylase, lysozome, and lingual lipase. Amylase starts the digestion of starch and lipase fat before the food is even swallowed. It has a pH optima of 7.4. Lingual lipase has a pH optimum ~4.0 so it is not activated till entering an acidic environment. Lysozyme acts to lyse bacteria. The presence of these things causes saliva to sometimes have a foul odor.
Functions
The functions of saliva include moistening food so it can be swallowed easily. Also, saliva contains the enzyme amylase, also called ptyalin, that breaks some starches down into maltose and dextrin.
(From Encyclopædia Britannica School Edition)
Beliefs
A common belief is that saliva contained in the mouth has natural disinfectants, which leads people to believe it is beneficial to "lick their wounds". Researchers at the University of Florida at Gainesville have discovered a protein called nerve growth factor (NGF) in the saliva of mice. Wounds doused with NGF healed twice as fast as untreated and unlicked wounds; therefore, saliva does have some curative powers in some species. NGF has not been found in human saliva; however, researchers find human saliva contains such antibacterial agents as secretory IgA, lactoferrin, and lactoperoxidase. It has not been shown that licking your wounds actually disinfects them.
Saliva is also known as spit. To spit or the action of spitting is also to expel saliva or other substances from the mouth. A verb for this action is to expectorate.
