SALIVARY GLANDS AND

THEIR SECRETION

PAROTID GLAND

Largest gland

Located anterior and Inferior to the Ear

Partially overlying the Masseter muscle

Produces 25-30 % of saliva

Conducted through the Parotid Duct to the Oral cavity.

SUB MANDIBULAR GLAND

Inferior to the body of the Mandible

Produce most of the saliva (60-70 %)

Ducts open through a Papilla in the floor of the mouth

lateral to the Lingual Frenulum

SUBLINGUAL GLAND

Inferior to the tongue

Internal to the Oral cavity Mucosa

each gland has multiple tiny sublingual ducts

Open on to the Inferior surface of the oral cavity

Posterior to the Submandibular duct papilla

contribute on 3-5% of total saliva

TYPES OF CELLS IN SALIVARY GLANDS

1.Mucous cells

Mucinogen

granules

Lubrication

and

Protection

Secretions

contains

“Mucin”

2. Serous CellsZymogen

Granules

Ptyalin

Precursors

Watery ,

contains SA

Digestion of

Starch

,maltose

COMPOSITION

FLOW RATE OF SALIVA

FUNCTIONS

MECHANISM OF FORMATION OF SALIVA

1. Primary secretion

2. Modification of saliva

MECHANISM OF FORMATION OF SALIVA

PRIMARY SECETION

•FORMED BY TRANSUDATION (Pressure filtration)•ISOTONIC TO PLASMA•MODIFIED AS SOON AS THEY SECRETED

IMP:EFFECT OF ALDOSTERONE ON DUCT CELLS

SYMPATHETIC STIMULATION

Sympathetic nerves (NE: Nor Epinephrine)

NEVia β-

Receptors

↑ cAMPExcytosis of

Enzymes

↑ Secretion

NE

↑ Ca2+

↑ Secretion

REFLEX REGULATION OF SALIVARY SECRETION

PHYSIOLOGICAL CONDITIONS

CEPHALIC PHASE SECRETION OF SALIVA BEFORE ENTRY OF FOOD

CONDITIONAL REFLEX

BUCCAL PHASE PRESENCE OF FOOD IN THE MOUTH [(+) BUCCAL RECEPTORS]

UNCONDITIONAL REFLEX& PARTIALLY REGULATED BY APETITE CENTRE

OESOPHAGEAL PHASE PASSING OF FOOD THROUGH OESOPHAGUS

STIMULATION OF SALIVARY GLANDS

GASTRIC PHASE PRESENCE OF FOOD IN STOMACH

IRRITANT FOODS IN STOMACH (VOMITING)

INTESTINAL PHASE FOOD IN INTESTINE IRRITANT FOOD IN UPPER INTESTINE

PHASES OF SALIVARY SECRETION

PHASES OF SALIVARY SECRETION

Cephalic Phase

Food

(Before entering)

Condition reflex

(Sight, Smell etc.,)

Secretion of Saliva

GASTRIC PHASE

Food (Mouth)

(+) Buccal Receptors

Secretion of Saliva

An Unconditioned reflex.

Partially regulated by Appetite Centre.

Esophageal Phase

Food passing through

Esophagus

(+) Salivary Glands

Gastric Phase & Intestinal Phase

Presence of Food in Stomach& Intestine (Irritants)

salivation before

Vomitting

ESOPHAGEAL PHASE GASTRIC AND INTESTINAL

PHASES

APPLIED PHYSIOLOGY

1. Salivary Duct Calculus: Blockage of Ducts

2. Xerostomia: Dryness of mouth due to decreased ↓ salivary

Secretion. Eg: Radiation Therapy.

3. Sialoliths: Crystalized Saliva deposits

4. Sialadenitis: Bacterial infections

5. Viral Infections: Mumps

6. Sialorrhoea: ↑ Salivary secretion