Good Essay About The Compositions And Functions Of Saliva

Saliva is secreted in through a number of endocrine glands (glands with ducts) into mouth cavity. Saliva’s general chemical makeup may vary from person to person but generally it consists of 99% water and has a number of electrolytes like chloride, magnesium, phosphate, bicarbonate, and calcium. The levels of these electrolytes differ in males and females and have a range of 2 mmol/l for the cations magnesium, calcium and inorganic phosphate and up to 30 mmol/l for chloride (Agha-Hosseini). Generally the pH is around acidic to neutral (Peterson). There is also a minor amount of other products like glucose, urea, cortisol and peroxide. Additionally, saliva glands also secrete a number of different proteins and peptides with a total protein concentration of 7mmol/l. These proteins can be large immunoglobulins or small antimicrobial peptides (e.g. LL-37, cathelicidin, defensins, histatins) (Hancock). There are also more specialized proteins like mucosal glycoproteins and amylin in the saliva. Like the gut the mouth also maintains a relative flora of bacteria (Yang).
Saliva has several functions. Salivary fluid first acts to lubricate the mouth for ingestion of food and liquid. Lubrication also helps when people are breathing and in some cases kissing. The different levels of electrolytes could help in maintaining the protein functions and the buffer capacity in the mouth. The different proteins have several functions. The mucosal glycoproteins act as a lubricant for the teeth and gums. Amylin is a key protein to break down sugars before going further in the digestive system. As the mouth is open to the outside world and is one of the main routes of infection it has armed itself with some defences. Firstly, it has antimicrobial peptides which bind to gram negative bacteria and destroy them by a number of mechanisms. Secondly, it has immunoglobins which bind to antigens that enter the mouth (Tenovuo). The normal bacteria is also important as many of these bacteria digest food particles. These bacteria can also be bad as they can contribute to formation of caries (Fang).

Works Cited

Agha-Hosseini, Farzaneh, Iraj Mirzaii Dizgah, and Sara Amirkhani. "The composition of unstimulated whole saliva of healthy dental students." J Contemp Dent Pract 7.2 (2006): 104-11.
Hancock, Robert EW, and Gill Diamond. "The role of cationic antimicrobial peptides in innate host defences." Trends in microbiology 8.9 (2000): 402-410.
Peterson, S., J. Woodhead, and J. Crall. "Caries resistance in children with chronic renal failure: plaque pH, salivary pH, and salivary composition." Pediatric research 19.8 (1985): 796-799.
Tenovuo, Jorma. "Antimicrobial function of human saliva-how important is it for oral health?." Acta Odontologica 56.5 (1998): 250-256.
Yang, Fang, et al. "Saliva microbiomes distinguish caries-active from healthy human populations." The ISME journal 6.1 (2012): 1-10.