JEEDA'S LOVE AND PASSION: SALIVA’S MYSTERIES

Saturday, January 5, 2013

SALIVA’S MYSTERIES

SALIVA’S MYSTERIES

Your saliva is doing all kinds of useful things for you all the time -- for instance, helping you chew and taste food. It's also home to more than 600 species of bacteria, which are harmlessly enjoying the moisture of your mouth.

Saliva is a watery substance located in the mouths of organisms, secreted by the salivary glands. It is composed of water, mucus, proteins, mineral salts, and amylase. Human saliva is composed of 99.5% water, and 0.5% consists of electrolytes, mucus, glycoproteins, enzymes, and antibacterial compounds

The enzymes found in saliva are essential in beginning the process of digestion of dietary starches and fats. As saliva circulates in the mouth cavity it picks up food debris, bacterial cells, and white blood cells. These enzymes also play a role in breaking down food particles entrapped within dental crevices, protecting teeth from bacterial decay. Saliva serves a lubricative function, wetting food and permitting the initiation of swallowing, and protecting the mucosal surfaces of the oral cavity from desiccation.

Human saliva contains proteins that can be informative for disease detection and surveillance of oral health. It contains many analytes of interest for screening, diagnosis and monitoring.

Functions

1. Digestion

· The digestive functions of saliva include moistening food and helping to create a food bolus. This lubricative function of saliva allows the food bolus to be passed easily from the mouth into the esophagus.

· Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars that can be later absorbed or further broken down in the small intestine.

· Salivary glands also secrete salivary lipase (a more potent form of lipase) to begin fat digestion. Salivary lipase plays a large role in fat digestion in newborn infants as their pancreatic lipase still needs some time to develop.

· It also contains small amounts of the digestive enzyme amylase, which chemically breaks down carbohydrates into simpler compounds.

2. Disinfectants

· Researchers find human saliva contains such antibacterial agents as secretory IgA, lactoferrin, lysozyme and peroxidase. 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.

3. Lubricates and moistens

· It lubricates and moistens the inside of the mouth to help with speech and to change food into a liquid or semisolid mass that can be tasted and swallowed more easily.

· It also helps soften food and spread it to your teeth so that you don't have to chew as hard.

4. Control the body’s water balance

· Saliva helps to control the body’s water balance; if water is lacking, the salivary glands become dehydrated, leaving the mouth dry, which causes a sensation of thirst and stimulates the need to drink.

5. Reduces tooth decay

· Saliva reduces tooth decay and infection by removing food debris, dead cells, bacteria, and white blood cells.

· It also has a protective function, helping to prevent bacterial build-up on the teeth and washing away adhered food particles.

6. Taste receptors

Saliva spreads molecules to the taste receptors on the tongue so you can tell whether something is salty, sour, sweet or spicy.

Spitting, or expectoration, is the act of forcibly ejecting saliva or other substances from the mouth. It is often considered rude and a social taboo in many parts of the world.

There is much debate about the amount of saliva that is produced in a healthy person per day; estimates range from 0.75 to 1.5 liters per day while it is generally accepted that during sleep the amount drops to almost zero. Three major pairs of salivary glands and many smaller glands scattered in the surface tissue of the cheeks, lips, tongue, and palate contribute to the total amount of saliva.

Small amounts of saliva are continually being secreted into the mouth, but the presence of food, or even the mere smell or thought of it, will rapidly increase saliva flow.