DEN 105 Lecture #5

What is a gland?

it is a structure that produces a chemical secretion necessary for normal bodily functions

Glandular tissue in the head and neck includes…

• Lacrimal

• Salivary

• Thyroid

• Parathyroid

• Thymus

Classification of glands

2 major types

• Exocrine

• Endocrine

Salivary glands- exocrine glands

produce saliva and are controlled by the autonomic nervous system (ANS)

Saliva

is a watery secretion with a pH of around 7. It is referred to as the “mouth’s bloodstream”

What role does saliva play?

plays an important role in bolstering and maintaining the health of oral soft and hard tissues

What is saliva made up as?

• Salivary amylase

• Lingual lipase

• Mucus

• lysozyme

• Immunoglobulin A (IgA)

• Electrolytes

Salivary amylase

an enzyme that begins starch digestion in the mouth

Lingual lipase

an enzyme that is activated by stomach acid and digest fat after the food is swallowed

Mucus

bind and lubricates the food mass and aids in swallowing

Lysozyme

an enzyme that kills bacteria and other pathogens

Immunoglobulin A (IgA)

an antibody that inhibits bacteria growth

Electrolytes

including sodium, potassium, chloride, phosphate, and bicarbonate

Function of saliva

• Helps prepare the bolus of food for easier swallowing

• Helps to keep the mucous membranes lubricated

• Helps prevent dehydration; dry mouth stimulus to drink water

• pH buffer

• Breaks down starches (carbohydrates)

• Cleanses teeth

• Neutralizes acids to prevent tooth decay

• Aids in taste

development of salivary gland

• arise from a cord or epithelium

• Grows to form a tube

• end of tube is either round or tubelike clusters

• Acini- cluster of secretory cells forms at the end of the tube

What are acini?

• Secretory end pieces

• Secrete proteins

• There are three types of secretory units (acini)

Three types of acini

• Serous acini

• Mucous acini

• Seromucous acini

Types of secretions

• Serous

• Mucous

• Seromucous

Serous

• Secretion is thin, watery, protein/enzyme-rich secretion

• Less viscous

Mucous

• Secretion is more viscous and mucin-rich

• 99% water

• Inorganic ions (e.g., sodium, potassium, and chloride)

• Minor amounts of amylase

• Has mucins: Key characteristic in their ability to form gels

Seromucous

has characteristics of both types of secretions

Major and Minor salivary glands

• are divided by size

• both major and minor salivary glands are exocrine glands and thus have ducts associated with them

• These ducts help drain the saliva directly into the oral cavity where the saliva can function

Major salivary glands

large paired glands and have maned ducts associated with them

Three major salivary glands

Parotid glands

Submandibular glands

Sublingual glands

Parotid salivary gland

• is the largest encapsulated major salivary gland

• the gland is divided into two lobes: the superficial and deep lobes

• Produces approximately 25% of saliva

• Predominantly serous secretions

Parotid salivary gland: Innervation

• The parotid salivary gland is innervated by the efferent (parasympathetic) nerves of the otic ganglion of the ninth cranial or glossopharyngeal nerve by way of the lesser petrosal nerve, as well as by the afferent nerve from the auriculotemporal nerve of the mandibular nerve of the fifth cranial or trigeminal nerve.

• However, the seventh cranial or facial nerve and its branches travel through the parotid salivary gland between its superficial and deep lobes to serve as a divider but are not involved in its innervation

Parotid salivary gland location

The parotid salivary gland occupies the parotid space, an area posterior to the mandibular ramus, anterior and inferior to the ear

Parotid salivary gland: Ducts

the duct associated with the parotid salivary gland is the parotid duct or Stenson’s duct

Parotid salivary gland duct location

• This long duct emerges from the anterior border of the gland, superficial to the masseter muscle.

• The duct pierces the buccinator muscle, and then opens up into the oral cavity on the inner surface of the buccal mucosa of the cheek, usually opposite the maxillary second molar

Parotid papilla

is a small elevation of tissue that marks the opening of the parotid duct on the inner surface of the cheek

Mumps

When the parotid salivary gland becomes enlarged and tender

This contagious viral infection usually involves inflammatory enlargement or parotitis of both glands, first one side and then the other, giving the characteristics “chipmunk” cheeks

Submandibular gland

is the second larges encapsulated major salivary gland

Produces approximately 60-65% of saliva

Mucous and serous secretions

Posterior to the sublingual gland

Wraps around the mylohyoid muscle

Submandibular salivary gland location

the submandibular salivary gland occupies the submandibular fossa in the submandibular space mainly in its posterior part

Submandibular salivary gland: duct

the duct associated with this gland is the submandibular duct or Wharton’s duct

Submandibular salivary gland: Wharton’s duct location

This duct travels along the anterior floor of the mouth then opens into the oral cavity at the sublingual caruncle, a small papilla near the midline of the floor of the mouth on each side of the lingual frenum

Submandibular salivary gland: innervation

it is innervated by the efferent (parasympathetic) fibers of the chorda tympani and the submandibular ganglion of the seventh cranial or facial nerve

Sublingual salivary gland

• is the smallest most diffuse, and only unencapsulated major salivary gland

• Approximately 10% of the total salivary volume

• Mixed serous and mucous secretion

Sublingual salivary gland: location

this gland occupies the sublingual fossa in the sublingual space at the floor of the mouth

Sublingual salivary gland: duct

• the short ducts associated with the gland sometimes combine to for the sublingual duct or Bartholin’s duct

• The sublingual duct then opens directly into the oral cavity through the same opening as the submandibular duct, the sublingual caruncle

Sublingual caruncle

is a small papilla near the midline of the floor of the mouth on each side of the lingual frenum

Ducts of Rivinus

other smaller ducts of the sublingual gland open along the sublingual fold

Sublingual salivary gland: innervation

has the same innervation as the submandibular salivary gland, which is by the efferent (parasympathetic) fibers of the chorda tympani and the submandibular ganglion of the seventh cranial or facial nerve

Minor salivary glands

are smaller than the larger major salivary glands but are more numerous in number; however, they are not individually encapsulated by surrounded by connective tissue within the submucosa

Minor salivary glands: Location

Most of the minor salivary glands are mainly scattered throughout the oral cavity in the buccal, labial, and lingual mucosa, the soft palate, the posterior part of the lateral zones of the hard palate, and the floor of the mouth.

What are the minor salivary glands, von Ebner’s glands associated with?

the base of the large circumvallate lingual papillae on the posterior part of the tongue’s dorsal surface

Where can the minor salivary glands also be found in?

• found in lesser numbers along the mucosa of the tonsils, supraglottis region, and paranasal sinuses as well as between the muscle fibers of the tongue

• They are not found in the gingival tissue and the anterior part of the lateral zones of the hard palate or its medial zone

Minor salivary glands: duct

• Each minor salivary gland has a single duct that secretes saliva directly into the oral cavity since they are exocrine glands like the major salivary glands.

• But the unnamed ducts of the minor salivary glands are shorter than those of the major salivary glands.

• All the minor salivary glands have a mainly mucous secretion with some serous secretion except for the glands of von Ebner which have only a serous secretion

Minor salivary glands: innervation

The minor salivary glands are innervated by various nerves depending on location

Lesions

• Salivary glands may become enlarged, tender, and possibly firmer due to various disease processes. They may also become involved in the formation of a salivary stone (or sialolith) within the gland, blocking the drainage of saliva from the duct, especially with the submandibular gland.

• Salivary gland obstruction may result in swelling and tenderness. Mucoceles (associated with minor salivary glands) and Ranulas (associated with the floor of the mouth) are salivary lesions caused by accumulation of mucus.

Salivary stones

• Salivary stones are uncomfortable but not dangerous, and can involve one or more enlarged, tender salivary glands. The clinician may also be able to palpate the stony hard salivary stone(s) during an examination.

• Facial radiographs or computed tomography (CT) can confirm the diagnosis. Salivary stones are usually removed manually or with minor surgery

Sialoliths

is a minor salivary gland on the floor of the mouth

Sialolithiasis

• When a salivary stone becomes lodged within the duct, causing a blockage of saliva. The gland usually swells and feels painful, especially around meal times, and infection may follow.

• Small stones may sometimes pass spontaneously or with conservative measures such as hydration, salivary stimulation, and gland massage.

• Antibiotics may be indicated when bacterial infection is present.

• Persistent stones may require minimally invasive removal or surgical treatment

Xerostomia

(DRY MOUTH) can result in increased trauma to a nonprotected oral mucosa, increased cervical caries, problems in eating, speech and mastication, and bad breath or halitosis.

Extensive cervical caries is a frequent complication of dry mouth. In addition to the lack of saliva, patients may attempt to stimulate salivary flow with sweets or chewing gums.

hyposalivation

reduced production of saliva

Treatment for dry mouth

• Being very vigilant about good oral hygiene through brushing and flossing

• Using a high-fluoride toothpaste (Prevident 5000)

• Sip water frequently

• Eat soft moist foods that are not overly salty

• Avoid rinses that contain alcohol

• Use products to moisturize your mouth including prescription or over-the- counter mouth rinses, artificial saliva or moisturizers to lubricate your mouth.

• Mouthwashes designed for dry mouth, especially ones with xylitol. Ex. Biotene or ACT mouthwashes

• Prescribe medication that stimulates saliva. Ex. pilocarpine (Salagen) to stimulate saliva production.