Information AboutSaliva |
| CATEGORIES ABOUT SALIVA | |
| body fluids | |
| digestive system | |
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Saliva is the watery and usually frothy substance produced in the mouths of Human s and some Animal s. In Animal s, '''saliva''' is produced in and secreted from the Salivary Gland s. 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 Starch es 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 Gland s 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. The acquired enamel pellicles in adults and children 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 . Discover Magazine, "The Biology of ...Saliva" October 2005 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 Pathogen ic. 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 . 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 Gland s, saliva is 98% Water , but it contains many important substances, including Electrolyte s, Mucus , Antibacterial compounds and various Enzyme s. It is a Fluid containing:
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