Parotid Gland - Anatomy & Physiology

ALIMENTARY SYSTEM MAJOR SALIVARY GLANDS

Parotid Salivary Gland

Parotid Salivary Gland - Copyright Nottingham 2008

• Serous secretion

• Moulded around base of auricular cartilage of ear

• Enclosed within facial covering

• Trabeculae divide gland into lobules

• Major ducts run within trabeculae and merge to form a single duct

• Duct opens in vestibule opposite 4th upper premolar (Not all species)

• Innervated by glossopharyngeal (CN IX) via trigeminal branch (CN V)

Development

1. Intercalated duct. Cuboidal cells.

2. Striated duct. Cuboidal cells with mitochondria in base.

3. Interlobular duct. Columnar to stratified columnar cells.

4. Stratified squamous epithelium continuous with epithelium lining oral cavity

Histology

• Basophilic endoplasmic reticulum

• Stratified squamous epithelium

• Tubulo-acinar gland

• Acinar cells surrounded by myoepithelial cells and basement membrane

Species Differences

Parotid Duct (Dog) - Copyright RVC

Carnivores

• Some mucous secretion in cat and dog

• Duct is superficial in dog

• Duct runs across masseter muscle in carnivores

Herbivores

• Larger gland and higher flow rate in herbivores to lubricate and soften food

• Duct is superficial in small ruminants

• Parotid gland extends rostrally over masseter muscle, ventrally to angle of jaw and caudally towards atlantal fossa

• Duct runs ventrally in herbivores below the mandible (facial groove in horses) before entering the oral cavity at the rostral margin of the masseter muscle

Equine

• Gland overlies the gutteral pouch

Links

Video Pot 258 Lateral section through the head of a dog