Salivary Glands: Function, Location, and Digestive Benefits

Salivary glands produce saliva, a complex fluid essential for oral health, digestion, and mucosal protection.

Major Glands (Paired)

• Parotid: Largest; serous secretion (amylase-rich); opens via Stensen's duct opposite maxillary 2nd molar.
• Submandibular: Mixed serous/mucous; produces ~65% of resting saliva; Wharton's duct opens at sublingual caruncle.
• Sublingual: Primarily mucous; multiple ducts of Rivinus + Bartholin's duct.

Minor Glands

600–1000 tiny glands in lips, buccal mucosa, palate, tongue, throat — mostly mucous; provide basal lubrication.

Saliva Composition

• Water (99%)
• Electrolytes (Na⁺, K⁺, Cl⁻, HCO₃⁻, Ca²⁺, PO₄³⁻, F⁻)
• Proteins: amylase, lipase, mucins, proline-rich proteins, statherin, histatins, cystatins, peroxidases, lysozyme, lactoferrin, sIgA, growth factors (EGF, NGF)

Key Functions

1. Digestion: Salivary amylase (ptyalin) initiates starch hydrolysis; lingual lipase (minor in adults) starts fat digestion.
2. Lubrication: Mucins coat mucosa, facilitate bolus formation, swallowing, speech.
3. Taste: Solubilizes tastants, transports to taste buds.
4. Protection: Buffering (bicarbonate, phosphate), pellicle formation, antimicrobial proteins, wound healing (EGF, histatins).
5. Dental integrity: Calcium/phosphate/fluoride for remineralization; clearance of sugars/acids.
6. Diagnostics: Salivary biomarkers for cortisol, hormones, drugs, HIV, SARS-CoV-2, oral cancer.

Dysfunction

Xerostomia (dry mouth) → caries, candidiasis, dysphagia, dysgeusia, speech difficulty, mucosal trauma. Causes: meds (anticholinergics #1), Sjögren's, radiation, dehydration, diabetes.

Management: sialogogues (pilocarpine, cevimeline), saliva substitutes, fluoride, treat underlying cause.