Lesson 62 pt.2: Structure and function of salivary glands

What type of glands produce saliva

Exocrine glands in the mouth

What are three functions of saliva

Digestive, lubricating, and protective functions

Besides digestive, lubricating, and protective functions, what other important function does saliva have

Buffering functions

How many pairs of major salivary glands are there

Three

Name the three pairs of major salivary glands

Parotid, mandibular, and sublingual glands

Where are the several minor salivary glands located

Throughout the oral mucosa

How are the minor salivary glands typically named

According to their location

Name four types of minor salivary glands

Labial, lingual, buccal, palatine, molar, or zygomatic

What type of gland is structurally similar in all species and composed of numerous lobules separated by thin connective tissue septa

Parotid Salivary Gland

What is the general shape of the parotid salivary gland

Roughly triangular

In horses, what does the parotid salivary gland partially overlay

The lateral wall of the guttural pouch

In carnivores and sheep, where does the parotid duct cross

The lateral surface of the masseter muscle

In the horse, ox, goat, and pig, where does the parotid duct travel

Along the ventral surface of the masseter muscle, medial to the angle of the jaw

Where does the parotid duct terminate

On a papilla, located opposite an upper third to fourth cheek tooth

In dogs, the parotid duct terminates opposite which tooth

Premolar 4

In the ox, the parotid duct terminates opposite which tooth

The 5th superior cheek tooth

In horses, small ruminants, and pigs, the parotid duct terminates opposite which teeth

The 3rd or 4th superior cheek teeth

What procedure can be done on the parotid duct in dogs to treat dry eye

Translocated from the mouth to the eye (keratoconjunctivitis)

Which major salivary gland is located close to the angle of the jaw and partially covered by the parotid salivary gland

Mandibular Salivary Gland

In carnivores, what is the general shape of the mandibular salivary gland

Largely ovoid

The mandibular salivary gland is situated subcutaneously and caudal to what other gland

The monostomatic salivary gland

What two veins is the mandibular salivary gland situated between in carnivores

The linguofacial (a) and maxillary vein (b)

In the dog, which two glands are of practical importance because they undergo cystic changes (ranula) that require removal

The mandibular and monostomatic salivary glands

What is the name for the cystic changes that the mandibular and monostomatic salivary glands undergo in the dog

Ranula

What can be disrupted as a result of cystic changes in the mandibular and monostomatic salivary glands

Mastication, swallowing, or prehension

What is the name of the single duct that drains the mandibular salivary gland

Mandibular duct

Where does the mandibular duct travel before it opens on the sublingual caruncle

Ventral to the mucous membrane floor of the mouth, close to the frenulum

The sublingual salivary gland consists of how many parts

Two

What are the two parts of the sublingual salivary gland

Monostomatic (compact) and Polystomatic (diffuse)

Which part of the sublingual salivary gland is situated more caudally

Monostomatic (compact)

Which part of the sublingual salivary gland drains by a single duct

Monostomatic (compact)

Which part of the sublingual salivary gland shares a common opening with the mandibular salivary duct

Monostomatic (compact)

Which part of the sublingual salivary gland is situated more rostrally

Polystomatic (diffuse)

How does the polystomatic sublingual gland drain

By several ducts

Where are the openings of the polystomatic sublingual gland ducts located

On a longitudinal fold in the lateral sublingual recesses

In cattle, the polystomatic sublingual gland openings are located on top of what structures

Conical papillae

Where is the parotid gland located relative to the auricular cartilage

At the junction of the head and neck overlying the basal portion of the auricular cartilage

Where is the parotid gland situated relative to the mandibular gland

Dorsal

Where is the zygomatic gland located

Ventral to the zygomatic arch

Where is the polystomatic gland located relative to the tongue

Beneath the mucosa on either side of the body of the tongue

What is the secretory component of each salivary gland called

The parenchyma

What is the supporting connective tissue of a salivary gland called

The stroma

What three types of secretions can salivary glands produce

Serous, seromucous, or mucous

What determines the type of secretion produced by a salivary gland

Its mucin content

Name the three epithelial cell types that compose each salivary secretory unit

Serous cells, Mucous cells, and Myoepithelial cells

What is the shape of serous cells

Pyramidal shape

What is the function of serous cells

Protein (enzyme) secreting cells

What spherical unit is created by serous cells joined apically by tight and adherent junctions

An acinus

What shape are mucous cells

Columnar shaped cells

What provides lubricating properties in saliva

Apical granules with hydrophilic mucins in mucous cells

In domestic mammals, what type of gland is the parotid salivary gland predominantly

Serous gland

What is the parotid salivary gland composed of

Compound acinar gland composed of numerous lobules separated by thin connective tissue septa

Where are myoepithelial cells located in the parotid salivary gland

Between the secretory cells and the basement membrane

The lumen of the acinus opens into what short duct

Intercalated duct

The intercalated duct joins a larger duct called what

Striated duct

What is the classification for both intercalated and striated ducts (where they are located)

Intralobular (within the lobule)

Interlobular ducts are located where

In the connective tissue septa between the lobules

What type of gland is the mandibular salivary gland

Seromucous (mixed) compound tubuloacinar gland

What is the halfmoon shaped cap of serous cells on a mucous unit in mixed salivary glands called

A serous demilune

The duct system of the mandibular salivary gland is similar to what other major salivary gland

Parotid

What type of gland is the sublingual salivary gland

Seromucous (mixed) compound tubuloacinar gland

Which of the major salivary glands is the smallest

Sublingual Salivary Gland

The sublingual glands of which three domestic animals are almost entirely mucous

Cattle, sheep, and pigs

Which two domestic animals' sublingual glands contain clusters of serous acini

Dogs and cats

Where are lingual glands located

In the submucosa between the intrinsic muscles of the tongue

What type of secretion do gustatory glands (associated with vallate and foliate papillae) produce

Entirely serous

Which minor salivary gland is only present in carnivores

Zygomatic salivary gland

Name three functions of saliva related to metabolic and nonmetabolic activities

Moistening the oral mucosa, moistening dry foods to aid swallowing, providing a medium for chemical stimulation of taste buds, buffering the content of the oral cavity, or digesting carbohydrates

What is the function of the high concentration of bicarbonate ions in saliva

Buffering the content of the oral cavity

What digestive enzyme in saliva breaks down carbohydrates

Alpha amylase

What substance in saliva controls the bacterial flora of the oral cavity

Lysosomes

What ions are essential in saliva for normal tooth development and maintenance

Calcium and phosphate ions

What two systems control the flow and secretion of saliva

Sympathetic and parasympathetic innervation (ANS)

Which branch of the autonomic nervous system is primarily important for the control of saliva flow and secretion

Parasympathetic

The mandibular and sublingual glands receive parasympathetic innervation via which cranial nerve

Cranial nerve VII

The parotid gland receives parasympathetic innervation via which cranial nerve

Cranial nerve IX

The external jugular vein is formed by the union of what two veins

The linguofacial and the maxillary veins

What is the main blood supply to the parotid salivary gland

Parotid artery, a branch of the external carotid

What is the largest artery supplying the mandibular salivary gland

Facial artery

In the horse, approximately how much saliva is produced daily

50L

In the pig, approximately how much saliva is produced daily

15 L/day

In the cow, approximately how much saliva is produced daily

100-200 L/day

What is the term for the community of microorganisms that live in the mouth of an animal (from conversation history)

The Oral Microbiome

The main blood supply to the head leaves the aorta through what artery

The brachiocephalic and then the left and right common carotid arteries

The common carotid arteries terminate by dividing into what two arteries

Internal and external carotid arteries

Which artery is the main continuation of the common carotid and supplies either half of the head

External carotid

What are the two terminating branches of the external carotid artery

Superficial temporal artery and Maxillary artery

Which of the two terminating branches of the external carotid artery is larger

Maxillary artery

Which artery is considered the main continuation of the external carotid

Maxillary artery

What is the general relationship between the veins and arteries of the head

The veins usually run as satellites to the corresponding arteries

What is the name of the branch of the facial artery that supplies the monostomatic portion of the sublingual salivary gland

Glandular branch of the facial artery

What is the name of the branch of the lingual artery that supplies the polystomatic portion of the sublingual salivary gland

Sublingual artery

During rumination, why does the saliva flow rate increase

Helps to buffer the fatty acids that are produced

What can interference with the normal flow of saliva to the stomach result in

Serious depletion of the electrolytes