SALIVARY GLANDS

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The salivary glands in mammals are exocrine glands that produce saliva.

Some released through ductal system.

They also secrete a chemical (enzymes) that breaks down starch into glucose.

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Human have three paired major salivary glands, including

Parotid

Submandibular

Sublingual

As well as hundreds of minor salivary glands.

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Salivary glands can also be classified as

Serous producing glands

Mucous producing glands

Seromucous (mixed)

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In serous secretions – the main protein secreted is alpha-amylase, an enzyme that breaks down starch into maltose and glucose

Mocous secretions – main protein secreted is mucin as lubricant

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The parotid glands are a pair of glands located in the subcutaneous tissues of the face overlying the mandibular ramus and anterior and inferior to the external ear.

The secretion produced by the parotid glands is serous in nature, and enters the oral cavity through the Stensen’s duct.

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Stensens duct opens in the rear of the mouth cavity near 2nd molar intraoally

Despite being the largest pair of glands, it produces approximately about 25% of saliva

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The submandibular glands are a pair of glands located beneath the floor of the mouth, superior to the digastric muscles.

The secretion produced is a mixture of both serous and mucous and enters the oral cavity via Wharton’s ducts.

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Approximately 70% of saliva in the oral cavity is produced by the submandibular glands, even though they are much smaller than the parotid glands

Risk of sialolithiasis ↑???

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The sublingual glands are a pair of glands located beneath the floor of the mouth anterior to the submandibular glands.

The secretion produced is mainly mucous in nature, however it is categorized as a mixed gland.

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Unlike the other two major glands, the ductal system of the subligual glands do not have striated ducts, and exit from 8-20 excretory ducts known as Rivinus ducts. While its major duct the Bartholin duct often joins the Wharton duct to open at the sublingual caruncle

Approximately 5% of saliva entering the oral cavity come from these glands

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There are over 600 to 1000 minor salivary glands located throughout the oral cavity within the submucosa of the oral mucosa.

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They are 1-2mm in diameter and unlike the other glands, they are not encapsulated by connective tissue only surrounded by it.

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Found in most oral submucosa in tissue of bucal, labial, and lingual mucosa, the soft palate, and lateral parts of hard palate and the floor of the mouth or btn muscles of the tongue

The minor salivary glands are innervated by facial nerve.

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(except for Von Ebner’s glands) which are found in tough circling the circumvallate papillae near the sulcus terminalis.

Von Ebner’s glands secretes purely serous fluid that begins lipid hydrolysis, and facilitate the perception of taste

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Salivary glands are innervated direct or indirect by the parasympathetic and sympathetic arms of autonomic nerve system.

Parasympathetic stimulation evokes a copies flow of saliva

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Parotid gland –receives parasympathetic input from glossopharyngeal nerve via otic ganglion

Submandibular and sublingual – receives parasympathetic input from facial nerve via submandibular ganglion

Direct sympathetic innervation via preganglionic nerves in the thoracic segments T1-T2

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Protection

Consist of protiens like mucins lublicate and protect both hard and soft tissue of the oral cavity.., mucin is principal organic constituent of mucus.

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The higher the saliva flow rate, the faster the clearance and the higher the buffer capacity.

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On the surface of the teeth to prevent wearing, the film consist of mucins and

proline –rich gycoprotein from saliva

inhibit demineralization and promote remineralization by attracting calcium ions

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Preventing demineralization that occurs when enamel disintegrates due to acid.

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Prevent microbial growth based on

1- elements it contains, eg lactoferrin in saliva binds naturally with iron, since Iron is a major component of bacterial cell wall, removal of iron results to cell wall breakdown.

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3- salivary immunoglobin A. serves to aggregate oral bacteria such as S.mutans and prevent the formation of dental plaque.

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Saliva can encourage soft tissue repair by decreasing clotting time and increasing wound contration.

Digestion

enzymes

Starch to maltose

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Saliva act as solvent in which solid particles can dissolve in and enter the taste buds.

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Presence of mucin water.

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Developmental

Inflammatory –sialoadenitis,sialolithiasis

Infection- mumps, etc

Neoplasm- begnin /malignant

Tumour- cysts –mucocele, Ranula

Sjögren’s syndrome

Xerostomia

Iatrogenic- unknown cause

Mention the major salivary glands

Describe type of secretions produced by each

What are the functions of saliva

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End

Briefly describe the contents of saliva and its respective function

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