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Babylon University College of Dentistry Babylon University College of Dentistry

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THE SALIVARY GLANDSBy :Ahmed Ali Abbas

Saliva

complex fluid found lubricating the mucosa and teeth of the oral cavity

secreted by the salivary glands Major Minor

Types of Saliva

salivary glands, their cells and ducts are greatly responsible for the modification and kind of saliva being secreted

It is of three types: Serous Saliva Viscous Saliva Mixed Saliva

Serous Saliva

Content: Amylase protein polysaccharides

Cell: Serous Cells “watery saliva” Glands that secrete this type:

Parotid Gland Von Ebner’s glands

Viscous Saliva

Content: Mucins (glycoproteins) Carbohydrates

Cell: Mucous Cells Thick and viscous Glands that secrete this type:

Sublingual Gland Minor Salivary Glands (except Von Ebner’s

glands)

Mixed Saliva

simply the combination of the aforementioned types of saliva

Able to do a multitude of significant functions Secreted by:

Submandibular Gland Sublingual Gland

Cells: Serous Cells Mucous Cells

Functions of Saliva

Main function: maintaining the well-being of the mouth

Other important functions: Protection Buffering Action Digestion Facilitation of Taste Defensive Action against Microbes Ionic Exchange between Tooth Surface

Functions of Saliva

MAJOR SALIVARY GLANDS

Major Salivary Glands

Functional Unit Parenchyma Stroma

In some books: salivon Three pairs:

Parotid glands Submandibular glands Sublingual glands

Parotid Glands

In front of the ear behind the ramus of mandible

Purely serous Ptyalin and IgA Stensen’s duct-

opens opposite the upper second molar

Parotid Glands

Nerve supply: CN V Sympathetic control:

superior cervical ganglion

Parasympathetic control: CN IX, oticganglion

Submandibular Glands

Inner aspect of the mandible below the floor of the oral cavity

Mixed, 90% serous 10% mucous Secretes lysozymes Wharton’s duct: opens at each side of the

sublingual folds

Submandibular Glands

Serous demilunes

1: intralobular ducts/ striated ducts2: mucous acinus3: serous demilunes

Submandibular Glands

Nerve supply: CN V Sympathetic

control: superior cervical ganglion

Parasympathetic control: CN VII, chorda tympani, submandibular ganglion

Sublingual Glands

Floor of the mouth, below the tongue

Mixed, more mucous Ducts of Rivinus Bartholin’s duct:

opens into Wharton’sduct

Sublingual Glands

Nerve supply: CN V Sympathetic control: superior cervical ganglion Parasympathetic control: CN VII, chorda

tympani, submandibular ganglion

MINOR SALIVARY GLANDS

MINOR SALIVARY GLANDS

Over 600 present in the oral cavity Types

Mucous producing minor salivary glands Serous fluid producing minor salivary glands

Mucous Producing Minor Salivary Glands Submucosa of the oral mucosa 1-2 mm in diameter Not encapsulated Number of acini connected in a tiny lobule

Serous Fluid Producing Minor Salivary Glands Aka. Von Ebner’s Glands Lipid hydrolysis and perception of taste Located around the foliate and circumvallate

papillae

Labial Glands

Inner surface of lips Mixed saliva Cells have distinct

mucoalbuminouscharacter

Terminal portions often form typicaldemilunes

Minor Buccal Glands

Continuation of the labial glands in the cheek Lie within the vicinity of the opening of the

parotid duct Drain into the third molar region Therefore, it is known as molar glands

Glossopalatine Glands

Pure mucous glands Continuation of the lesser sublingual glands

(posteriorly) Ascend in the mucosa of the glossopalatine

fold

Palatine Glands

Pure mucous glands Occupy the roof of the oral cavity Divided into the glands of the:

Hard palate Soft palate and uvula

Glands of the Tongue

Anterior lingual gland Anterior part- chiefly mucous Posterior part- branching tubules lined with

mucous cells and capped with demilunes of serous cells

Posterior lingual glands Base of the tongue- purely mucous Glands of the vallate papillae (Von Ebner’s

glands)- purely serous, opens into the trough (depression) of the vallate papillae

Glands of the Tongue

Von Ebner’s Glands

STRUCTURES OF SALIVARY GLANDS

STRUCTURES OF SALIVARY GLANDS Parenchyma of glands consists of:

Secretory Portions Branching Duct Sytem

Lobules Septae Capsule

SECRETORY PORTIONS

Serous Cells Seromucous cells Resemble truncated

pyramids Tight junctions Junctional

complexes Collectively, serous

acini

Apical Cytoplasm of Serous Cells containing secretory granules

Mucous Cells

Adapted for production, storage, and secretion of proteinaceous material

Mucins Collectively, mucous

acini

Mucous Cells in tubulard secretory end pieces.

Mucous cells showing the serous demilunes.

Myoepithelial Cells

Flattened stellate cells

Desmosomes

Myoepithelial Cells

DUCTAL SYSTEM

Intercalated Ducts

Classified as intralobular duct

Smallest branch of the system of ducts

Prominent in Salivary Glands

Frequent in Parotid Gland

Striated Ducts

Formed by union of Intercalated Ducts

Terminal Excretory Ducts

Special eosinophilic cells

Terminal Excretory Ducts

Interlobular excretory duct

Development of Salivary Glands Derived from the oral mucosa Arise in weeks 5-6 of embryonic life

Development of Salivary GlandsPRIMORDIA TIME OF

DEVELOPMENT

EMBRYONIC ORIGIN

REGION

Parotid gland primordia (anlage)

5th to 6th week Ectoderm Labiogingival sulcus

Submandibular gland primordia

6th week Endoderm Hyoid arch

Sublingual gland primordia

7th to 8th week Endoderm Linguogingival sulcus

Intraoral minor salivary glands

3rd month

Development of Salivary Glands

AGE CHANGES

Age Changes

the aging salivary glands are known to undergo structural changes

The lobule structure becomes less ordered The acini vary more in size and eventually atrophy Interlobular ducts become more prominent and the

percentage of fibroadipose tissue increases

Age Changes

Changes in the salivary glands (submandibular,parotid (less) and minor salivary glands) Shrinkage of cells Dilation of ducts Oncocytic transformation Increased adiposity Fibrosis Focal microcalcifications with obstruction Chronic inflammation

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