Salivary Gland Parotid Gland Submandibular gland Sublingual gland

Salivary Gland

Parotid Gland. Submandibular gland. Sublingual gland. Minor salivary glands in floor of mouth, pharynx, tongue & cheeks

Secretory unit : Acinus • • Acinar cells Intercalated duct cells. Striated Duct cells. Secretory Duct cells. • • Mechanism of secretion of Saliva Active secretion Primary secretion Modification of primary secretion

Parotid gland: Entirely serous gland. Largest salivary gland. Rich in water and electrolyte and lack mucin. 25% of total salivary secretion. Duct of Stensen - level of 2 nd molar teeth

Sublingual Gland: Predominantly gland. Sublingual mucous duct(Ducts of Rivinus) Mucous : serous = 4: 1 5% of total salivary secretion

Submandibular Gland : Mixed type. Ducts of Wharton (Submandibular ducts). 70% of total salivary secretion

Serous cells : Digestive enzymes. Mucous cells: Mucin. Intercalated and striated cells: Modifies the ionic composition of the saliva.

Blood flow: Blood flow and metabolism secretion. 10 times α rate of saliva than the active skeletal muscle. Parasympathetic stimulation- increase in salivary secretion.

Nerve supply

1. EFFERENT NERVE SUPPLY: - Parasympathetic nerve supply - Sympathetic nerve supply 2. AFFERENT NERVE SUPPLY: - VII & IX cranial nerves •

Saliva First digestive juice to come in contact with food Composition of saliva: Rate of secretion : 1 ml / min; Daily secretion: 1 -1. 5 L / day. Max during meals and minimum during sleep. p. H = < 7 Color= colorless.

Saliva Solid(0. 5%) Water(99. 5%) Inorganic (0. 2%) Organic (0. 3%) Na+ , Cations K+ , Ca 2+ , Mg 2+ Anions Cl- , Hco 3 - , Po 4 -

Organic substances : Enzymes: Ptyalin/Salivary amylase Lingual lipase, Kallikreins Mucin Lysozymes Nerve growth factors Immunoglobulins Proteins

Regulation of salivary secretion: Exclusively regulated by Neural mechanism 1. Spontaneous secretion 2. Reflex secretion

Spontaneous secretion In the absence of any known stimulation. Exp: Atropine and Cyanide. Depends on the metabolic activity of the gland. v Keeps the oral cavity moist.

Reflex secretion Unconditioned reflex : Stimulus: Presence of food in the oral cavity Previous experience not necessary Conditioned reflex Stimulus: Sight, Smell, Thought Based on previous experience

Functions of saliva: ü Preparation lubrication. ü Solventü Help of the food for swallowing and Taste sensation. in speech. ü Digestion. ü Cleansing action. ü Regulation of water balance. ü Excretory function.

Applied aspects: 1. Xerostomia / Aptyalism: Complete absence of salivary secretion. Congenital absence of salivary gland. 2. Sialorrhoea: Increase salivary secretion. Pregnancy, tumor of the gland.

3. Hypo secretion: Decrease in salivary secretion. Anxiety , Fear, Dehydration. 4. Chorda tympani syndrome: Sweat secretion instead of salivary secretion while having food. Misdirected growth of the nerve to the sweat glands of submental region.

5. Mumps: Enlargement of the gland. Viral infection of the parotid gland. 6. Sailolithiasis: Stone formation in the salivary gland/ducts.

7. Crocodile tears: Tear secretion instead of salivary secretion while having food. Misdirected growth of the facial nerve to the Lacrimal gland.