salivary gland histology

Salivary Glands

Dr Prennie VidieraFather Muller Homoeopathic Medical College & Hospital

• Parotid glands

• Submandibular glands

• Sublingual glands

• Numerous small glands situated in the mucous membrane

– Lips : labial glands

– Cheeks: buccal glands

– Tongue: lingual glands

– Palate: palatine glands

• Secretions,

– Keep mouth moist

– Protection

– Lubrication

– Enzymes (amylase & lysozymes)

– Immunoglobulin A

• Salivary glands are compound tubulo-alveolar glands (racemose)

• Secretory elements (end pieces/portioterminalis)

may be

rounded (acini)

pear shaped (alveoli)

tubular

mixture (tubulo-acinar or tubulo-alveolar)

secretory element

lead into

Series of ducts

through

Secretions are poured into the oral cavity

• On section,

large number of closely packed acini/alveoli

Ducts scattered between them

• Supported by connective tissue

Connective tissue,

• divides glands into lobules

• forms capsules

Blood vessels, lymphatics and nerves run in the

connective tissue

Alveoli

• Cell lining are serous / mucous

Serous

Stain darkly

(zymogengranules)

Rounded nuclei

Towards the base

Mucous

Stains lightly

Appears empty

Cells filled with mucoid

materials

Flattened Nuclei towards

basements

Alveolus

• Made up of serous or mucous cells

• Some cases,

mucous alveoli are covered by groups of serous cells

arranged in the form of

Crescents or demilunes

Alveolus in,

parotid gland – entirely serous

occ, mucous

submandibular gland – mixed

Sublingual gland – mucous

• Secretory unit/ gland,

with only one type of cell – homocrine

more than one variety – heterocrine

All the 3 major salivary glands are heterocrine

Secretions produced in alveoli pass along

A system of ducts (different parts of these have differing structure)

smallest ducts

Intercalated ducts lined by

Cuboidal / flattened cells open into

Straited ducts Lined by

Columnar cells

Open into

Excretory ducts

Lined by

Simple columnar epithelium

Myoepithelial cells

• Present in relation to alveoli & intercalated ducts of salivary glands.

• On alveoli, these are branched.

• On ducts, these are fusiform & run longitudinally

• Cilia are present on some

• These are contractile

• Contractions help to squeeze out secretion from alveoli