Objectives To be familiar with the anatomy and innervation of the major salivary glands To be familiar with the functions of saliva, the differences in salival composition among the glands, and to understand the factors that affect salivary flow To be familiar with the tonsils, their location, and their function

Parotid tumor

What are salivary glands? 3 major glands: Parotid Submandibular Sublingual Plus many accessory glands in mucosa Exocrine glands that secrete directly into the oral cavity Important for lubricating mouth, remineralizing teeth, breaking down food Innervated by sensory, parasympathetic, and sympathetic fibres

Salivary Glands Overview Parotid gland Sublingual gland Submandibular gland

The parotid and other structures

Under the parotid

The parotid and the mandible

Parotid duct and Buccinator

Opening to the parotid duct (parotid papilla)

Histology of the Parotid Gland compound racemose gland large number of ducts arranged in branching system Mostly serous alveoli with cuboidal- or columnar-lined ducts

Summary of the Parotid Largest of the salivary glands Mostly watery serous secretion Closely associated with facial nerve and vasculature of the face Parotid duct opens through cheek above upper second molar Produces most stimulated saliva

Submandibular gland and the mylohyoid muscle Sublingual gland

Openings to the submandibular and sublingal glands Both glands join common sublingual duct that opens below the base of the tongue in the sublingual papilla.

Sublingual papilla

Histology of the submandibular gland Mixed gland with serous and mucous alveoli Ducts and lobules present, but not as extensive as in parotid Demilunes are granular serous secreting cells

Factors Affecting Salivary Flow Important Factors Unimportant Factors Degree of hydration Body position Exposure to light Olfaction Previous stimulation Circadian rhythms Circannual rhythms Drugs Gender Age (above 15 years) Body weight Gland size Psychic effects --thought/site of food --appetite --mental stress Functional stimulation

Properties of Individual glands Parotid Submandibular Sublingual Serous Intermediate Viscous High amylase Low calcium High calcium 20% unstimulated volume 65% unstimulated volume 7-8% unstimulated volume 50% stimulated volume

Innervation of the Salivary Glands Main control by parasympathetic system: Submandibular and sublingual: Via chorda tympania of facial nerve through submandibular ganglion Parotid: Glossopharyngeal nerve via otic ganglion Sympathetic fibres through cervical ganglion then follow blood vessels to glands

Parasympathetic Innervation

What are tonsils? Mucosa-associated lymphoid tissue (MALT). Ring the junction of the oral cavity and orophayrnx and nasal cavity and nasopharynx. Participate in immune responses to foreign substances inhaled or ingested. Located in lamina propria of mucosa. Five tonsils: pharyngeal (adenoid), palatine (x2), lingual (x2).

Palatine tonsils

Where are the tonsils?

Tongue view of tonsils

Acute Tonsilitis