HISTOLOGY OF SALIVARY GLANDS

Dr. Sobia IbrahimAssistant Professor Anatomy,KEMU

Saliva is produced by Three major salivary glandsParotidSubmandibularSublingualNumerous minor salivary glands

Saliva is a hypotonic watery secretion It contains mucous,Enzymes,Secretory antibodies, Inorganic salts.Daily production is 600-1500ml in human

GENERAL STRUCTURE OF SALIVARY GLANDS

STROMA

Capsule

Septa

Blood vessels & nerves

Ducts

Lobule

PARENCHYMA

Accini

Duct system

Each gland is surrounded by a connective tissue capsule

From capsules, multiple septae are thrown inwards to divide the parenchyma into incomplete lobules

Within each lobule many secretory acini are surrounded by fine loose C.T .

Blood vessels, lymphatic vessels, nerves and excretory ducts travel through septa.

PARENCHYMA

Glands are tubuloacinar variety

Acini consists of secretory cells which have a lumen in middle going to duct

Serous, mucous or mix.

Myoepithelial cells lie between plasmalemma and basal lamina of secretory cells

MUCOUS & SEROUS ACCINI

DUCT SYSTEM INTERCALATED DUCTS

Lined by cuboidal epithelium

STRIATED DUCT Lined by columnar cells

& show Radial striations INTERLOBULAR/ EXCRETORY DUCTS- in

CT septa Proximally-

pseudostratified/stratified cuboidal

Distally – stratified columnar

MAIN DUCT Non keratinized stratified

squamous epithelium

PAROTID GLAND BRANCHED ACCINAR gland

SEROUS

Striated & intercalated

ducts in parenchyma

Interlobular duct in CT

septa

Plasma cells present in CT

septa

Secretory products has:

Amylase

Proline- rich protien

which has

calcium binding

properties

SUBMANDIBULAR GLAND

BRANCHED TUBULOACCINAR

gland

Predominantly SEROUS

Majority serous accini

Mucous accini with serous

demilunes-10%

Well developed striated ducts

Underdeveloped intercalated

ducts

Secretory products have:

Amylase

Proline rich protiens

Lysozymes

SUBLINGUAL GLAND

BRANCHED

TUBULOACCINAR gland

Predominantly mucous

Serous cells only as

demilunes

Striated & intercalated

ducts not well

developed

Secretory products :

Amylase

Lysozymes

COMPARISON

MINOR SALIVARY GLANDS

Scattered throughout oral mucosa & submucosa

Nonencapsulated

Usually MUCOUS

Exception is von Ebner gland of tongue

Short ducts open on oral mucosa

B lynmphocytes releasing IgA common

MEDICAL APPLICATION

Reduced function of major salivary glands due to

disease / radiotherapy

RESULTS:

◦ Caries

◦ Atrophy of oral mucosa

◦ Speech difficulties

SEROUS CELL

Pyramidal cells. Broad end facing the

basement membrane and narrow end facing lumen.

6-8 in no. Apex has microvilli Basal region has rounded

nucleus. Basal region have

abundant RER (due to which basal region stain basophilic)and mitochondria.

Apical region : zymogen (secretory) granules ,so apical region is acidophilic

Adjacent serous cell joined by junction near apices.

Intercellular canaliculi

FUNCTION: thin and watery secretions

MUCOUS CELL

Tall cuboidal or low columnar cells with basal flattened nuclei.

Apical region has mucinogen granules.

H&E stain mucous poorly so muous cells appear empty.

Well developed golgi apparatus.

E/M: junctional complexes, no intercellular canaliculi.

Cells secrete mucinogen which on contact with water form mucous.