Salivary

Salivary is an adjective relating to saliva, the watery secretion produced by the salivary glands in the oral cavity. Saliva plays a key role in digestion, lubrication, oral protection, and taste. In humans, the major glands are the parotid, submandibular, and sublingual glands, supplemented by numerous minor glands, with ducts delivering saliva into the mouth. Unstimulated saliva is produced continuously, and flow increases with stimulation such as chewing or smelling food.

Composition and properties: Saliva is mostly water but also contains electrolytes (including bicarbonate to help buffer acids), mucus for lubrication, enzymes such as salivary amylase that begins carbohydrate digestion, and lingual lipase. It also carries antimicrobial substances like lysozyme, lactoferrin, and secretory IgA, along with various proteins that support oral health. The composition and viscosity of saliva vary with flow rate and can be influenced by age, medications, and health status.

Functions: Saliva moistens and lubricates the mouth, aiding speech and swallowing. It begins digestion through amylase, provides a protective pH buffer to teeth, and contributes minerals such as calcium and phosphate for remineralization of enamel. The antimicrobial components help control oral microbes, supporting caries and plaque management.

Regulation and variability: Salivary secretion is regulated by the autonomic nervous system. Parasympathetic activity tends to produce copious, watery saliva, while sympathetic activity yields a more protein-rich, viscous saliva. The timing and quality of saliva adapt to taste, mastication, and circadian rhythms.

Clinical relevance: Dry mouth (xerostomia), caused by medications, dehydration, autoimmune conditions like Sjögren’s syndrome, or radiation, can affect comfort and health. Disorders of salivary glands, such as sialolithiasis or infections, may alter flow or composition. Diagnostic approaches include sialometry and, for duct visualization, sialography.