Saliva

Jump to navigation Jump to search

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Overview

WikiDoc Resources for Saliva

Articles

Most recent articles on Saliva

Most cited articles on Saliva

Review articles on Saliva

Articles on Saliva in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Saliva

Images of Saliva

Photos of Saliva

Podcasts & MP3s on Saliva

Videos on Saliva

Evidence Based Medicine

Cochrane Collaboration on Saliva

Bandolier on Saliva

TRIP on Saliva

Clinical Trials

Ongoing Trials on Saliva at Clinical Trials.gov

Trial results on Saliva

Clinical Trials on Saliva at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Saliva

NICE Guidance on Saliva

NHS PRODIGY Guidance

FDA on Saliva

CDC on Saliva

Books

Books on Saliva

News

Saliva in the news

Be alerted to news on Saliva

News trends on Saliva

Commentary

Blogs on Saliva

Definitions

Definitions of Saliva

Patient Resources / Community

Patient resources on Saliva

Discussion groups on Saliva

Patient Handouts on Saliva

Directions to Hospitals Treating Saliva

Risk calculators and risk factors for Saliva

Healthcare Provider Resources

Symptoms of Saliva

Causes & Risk Factors for Saliva

Diagnostic studies for Saliva

Treatment of Saliva

Continuing Medical Education (CME)

CME Programs on Saliva

International

Saliva en Espanol

Saliva en Francais

Business

Saliva in the Marketplace

Patents on Saliva

Experimental / Informatics

List of terms related to Saliva

Saliva is the watery and usually frothy substance produced in the mouths of humans and some animals. In animals, saliva is produced in and secreted from the salivary glands.

Functions

Digestion

The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach. Salivary glands also secrete enzyme to start fat digestion. This is useful for infants to digest the fat in milk.

Role in emesis

The importance of the salivary protective function can be demonstrated by considering a scenario where an individual is about to vomit. Vomit contains gastric substances which are extremely acidic and will erode teeth. A protective reflex occurs before the individual prepares to vomit. Signals are sent from the brain to the salivary glands via the involuntary nervous system to cause increased saliva secretion, even before vomiting occurs. Thus, when vomiting does occur, there is already saliva present in the mouth acting to minimize the acidity and thus prevent destruction of tooth structure.

Pellicle deposits

In addition to this, saliva is responsible for depositing salivary pellicle that covers the entirety of the tooth surfaces. This pellicle is believed to play a role in plaque formation, though there is evidence that it may also act as a protective barrier between acids and the tooth surface.[1]

Disinfectants

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.[2] It has not been shown that human licking of wounds disinfects them, but licking is likely to help clean the wound by removing larger contaminants such as dirt and may help to directly remove infective bodies by brushing them away. Therefore, licking would be a way of washing, useful if purer water isn't available to the animal or person.

The mouth of animals is the habitat of many bacteria, some of which may be pathogenic. Animal (including human) bites are routinely treated with systemic antibiotics because of the risk of septicemia.

Stimulation

The production of saliva is stimulated both by the sympathetic nervous system and the parasympathetic.[3]

The saliva stimulated by sympathetic innervation is thicker, and saliva stimulated parasympathetically is more watery.

Daily salivary output

There has been some disagreement regarding the daily salivary output in a healthy individual. Today, it is believed that the average person produces approximately 700mL of saliva per day, which is much less than was once thought.

Contents

Produced in salivary glands, saliva is 98% water, but it contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes. [4]

It is a fluid containing:

  • Water
  • Electrolytes:
  • Mucus. Mucus in saliva mainly consists of mucopolysaccharides and glycoproteins;
  • Antibacterial compounds (thiocyanate, hydrogen peroxide, and secretory immunoglobulin A)
  • Various enzymes. There are three major enzymes found in saliva.
    • α-amylase (EC3.2.1.1). Amylase starts the digestion of starch and lipase fat before the food is even swallowed. It has a pH optima of 7.4.
    • lysozyme (EC3.2.1.17). Lysozyme acts to lyse bacteria.
    • lingual lipase (EC3.1.1.3). Lingual lipase has a pH optimum ~4.0 so it is not activated till entering an acidic environment.
    • Minor enzymes include salivary acid phosphatases A+B (EC3.1.3.2), N-acetylmuramyl-L-alanine amidase (EC3.5.1.28), NAD(P)H dehydrogenase-quinone (EC1.6.99.2), salivary lactoperoxidase (EC1.11.1.7), superoxide dismutase (EC1.15.1.1), glutathione transferase (EC2.5.1.18), class 3 aldehyde dehydrogenase (EC1.2.1.3), glucose-6-phosphate isomerase (EC5.3.1.9), and tissue kallikrein (EC3.4.21.35).
  • Cells: Possibly as much as 8 million human and 500 million bacterial cells per mL. The presence of bacterial products (small organic acids, amines, and thiols) causes saliva to sometimes exhibit foul odor.
  • Opiorphin, a newly researched pain-killing substance found in human saliva.


References

  1. The acquired enamel pellicles in adults and children
  2. Discover Magazine, "The Biology of ...Saliva" October 2005
  3. Essentials of Human Physiology by Thomas M. Nosek. Section 6/6ch4/s6ch4_7.
  4. Essentials of Human Physiology by Thomas M. Nosek. Section 6/6ch4/s6ch4_6.

External links


ar:لعاب zh-min-nan:Chhùi-noā bar:Schlaz bg:Слюнка ca:Saliva da:Spyt de:Speichel et:Sülg hr:Slina io:Salivo id:Air liur it:Saliva he:רוק (ביולוגיה) la:Saliva lt:Seilės hu:Nyál nl:Speeksel no:Spytt simple:Saliva sl:Slina sr:Пљувачка fi:Sylki sv:Saliv ta:உமிழ்நீர் uk:Слина yi:שפייאכץ

Template:Jb1

Template:WS