histology of salivary glands dr. sobia ibrahim assistant professor anatomy, kemu

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.