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From Digestive System
Sublingual Glands
Salivary glands beneath the tongue.
Overview
The sublingual glands are one of the three major pairs of salivary glands in the human body, along with the parotid and submandibular glands. They are the smallest and most deeply situated of the major salivary glands and primarily secrete mucous saliva. These glands play a key role in lubricating the oral cavity and initiating digestion.
Location
The sublingual glands are located in the anterior floor of the mouth, specifically:
Underneath the mucous membrane of the floor of the mouth
Anterior and superior to the submandibular glands
Lateral to the tongue and above the mylohyoid muscle
Each gland lies beneath the tongue and causes a slight elevation called the sublingual fold
Structure
The sublingual glands are almond-shaped and approximately 3–5 grams in weight. Key structural features include:
Numerous short ducts: Typically 8–20 small ducts called ducts of Rivinus that open along the sublingual fold
Bartholin’s duct: In some individuals, a larger duct may join the submandibular (Wharton’s) duct to drain into the sublingual caruncle
Mucous acini dominant: The gland contains mostly mucous cells with a few serous demilunes, giving rise to thick, viscous saliva
Arterial supply: Branches from the lingual and facial arteries
Venous drainage: Via the sublingual and facial veins
Innervation: Parasympathetic fibers from the facial nerve (CN VII) via the chorda tympani and submandibular ganglion
Function
The sublingual glands perform several essential functions:
Secretion of saliva: Produce mostly mucous-rich saliva that lubricates the floor of the mouth and tongue
Support in digestion: Initiates the breakdown of starches through salivary enzymes (minor contribution compared to other glands)
Moistening mucosa: Keeps oral tissues hydrated and helps in speech and swallowing
Physiological Role(s)
The sublingual glands contribute to overall oral and digestive health by:
Continuous basal secretion: Unlike the parotid glands, they secrete continuously to maintain oral moisture
Mucosal protection: The viscous saliva coats the oral mucosa, protecting it from mechanical trauma and dehydration
Antimicrobial activity: Saliva contains protective components like lysozyme and IgA that inhibit microbial growth
Facilitation of taste and speech: Saliva acts as a solvent for taste molecules and aids in phonation
Clinical Significance
The sublingual glands, though small, are clinically relevant in several conditions:
Ranula: A mucous retention cyst that forms when a sublingual duct is blocked; appears as a bluish swelling in the floor of the mouth
Sialolithiasis (salivary stones): Less common in the sublingual gland compared to the submandibular gland, but can still occur and cause swelling or infection
Sialadenitis: Inflammation of the gland due to infection or obstruction; may present with pain, swelling, and purulent discharge
Neoplasms: Sublingual gland tumors are rare but more likely to be malignant than those in other salivary glands
Surgical significance: Care is needed during procedures in the floor of the mouth to avoid damaging the sublingual gland or ducts
Xerostomia (dry mouth): Dysfunction or removal of salivary glands, including the sublinguals, can reduce saliva and impact oral health
Evaluation of the sublingual glands includes clinical examination, ultrasound, MRI, and sometimes sialography. Management of gland-related issues ranges from conservative treatment to surgical excision.
Did you know? The body absorbs over 90% of the nutrients from the food you eat in the small intestine.