Oral Tissues and Salivary Glands

Question 1

What are the major structures of the oral cavity?

Answer 1

Lips
Teeth
Tongue
Oral mucosa
Associated salivary glands

Question 2

What is the epithelium of the oral mucosa?

Answer 2

Stratified squamous with keratinisation in areas of friction e.g. the palate

Question 3

What is the lamina propria that supports the mucosa made of?

Answer 3

Dense collagenous tissue

Question 4

Where is the lamina propria connected to the underlying muscle by loose submucosal supporting tissue?

Answer 4

Highly mobile areas e.g. floor of the mouth and soft palate

Question 5

True of False: In areas where the oral mucosa overlies bone, the lamina propria is tightly bound to the periosteum by a relatively dense fibrous submucosa.

Answer 5

True

Question 6

List the types of oral mucosa.

Answer 6

1. Lining
2. Masticatory
3. Specialised

Question 7

Describe lining mucosa.

Answer 7

Mainly non-keratinised stratified squamous epithelium with underlying supportive lamina propria that lines the inner lips, cheeks, soft palate, floor of mouth and underside of the tongue

Question 8

What type of epithelium is masticatory mucosa?

Answer 8

Keratinised/para-keratinised stratified squamous epithelium

Question 9

Where is masticatory mucosa found?

Answer 9

Hard palate and the gingiva (gums around the teeth)

Question 10

What is an example of specialised mucosa?

Answer 10

The dorsal surface of the tongue has taste buds, is keratinised and has numerous papillae

Question 11

What are the surfaces of the lip?

Answer 11

1. Outer cutaneous
2. Red (vermillion) border
3. Inner oral mucosa

Question 12

Describe the outer cutaneous surface of the lip.

Answer 12

Thin skin
Epidermis with hair follicles, sebaceous gland and sweat glands
Underlying dermis
Rich sensory innervation

Question 13

What is the vermillion border?

Answer 13

Transition zone between skin and oral mucosa
Thick stratified squamous epithelium with either no keratin or light keratin
Tall C.T. papillae under epithelium
Pink/red
Lacks hair follicles and no glands

Question 14

What are the labial glands?

Answer 14

Small groups of minor salivary glands deep to the oral mucosa lamina propria

Question 15

Is the core of the lip skeletal, smooth or cardiac muscle?

Answer 15

Skeletal

Question 16

What is the purpose of the palate?

Answer 16

Forms roof of mouth and separates oral and nasal cavities

Question 17

Is the hard palate anterior or posterior?

Answer 17

Anterior

Question 18

Describe the hard palate.

Answer 18

Covered by masticatory mucosa with rugae
Underlying lamina propria with papillae containing many capillaries and lymphocytes
Ducts connect palatine glands to epithelial surface

Question 19

What is the uvula?

Answer 19

A conical projection on the posterior aspect of the soft palate

Question 20

What is the soft palate’s function?

Answer 20

To close off the nasopharynx from the oropharynx during swallowing

Question 21

What is the lining of the soft palate?

Answer 21

Oral: Non-keratinised stratified squamous
Nasal: Ciliated pseudostratified columnar with goblet cells

Question 22

Why is the soft palate red?

Answer 22

Rich vascular supply

Question 23

What is the tongue?

Answer 23

Mobile muscular organ on the floor of the oral cavity, involved in mastication, swallowing, speech and taste

Question 24

What is the sulcus terminalis?

Answer 24

A V-shaped groove on the dorsum of the tongue that demarcates the anterior 2/3 from posterior 1/3

Question 25

What embryological tissue is the epithelium of the tongue made of?

Answer 25

Anterior: Oral ectoderm Posterior: Foregut endoderm

Question 26

What are the 4 types of lingual papillae?

Answer 26

1. Filiform 2. Fungiform 3. Circumvallate 4. Foliate

Question 27

True or False: The posterior 1/3 of the dorsal tongue has numerous lingual papillae.

Answer 27

False, instead studded by 35-100 irregular mucosal bulges that correspond to lingual tonsils creating a cobblestone appearance

Question 28

What is the composition of the body of the tongue?

Answer 28

A mass of interlacing bundles of skeletal muscle (allowing a wide range of movements) bound to the mucous membrane by a dense collagenous lamina propria which is continuous with the epimysium of the muscle

Question 29

What papillae type are very numerous and a keratin-tipped elongated conical shape?

Answer 29

Filiform papillae

Question 30

What is the role of filiform papillae?

Answer 30

Provide a rough surface that facilitates food movement during chewing

Question 31

Describe fungiform papillae.

Answer 31

Less numerous than filiform Keratinised mushroom shape with scattered taste buds on the upper surface

Question 32

Where are the majority of fungiform papillae located?

Answer 32

Near the tip of the tongue

Question 33

What is the structure of foliate papillae?

Answer 33

Parallel ridges and furrows on the side of the tongue and have taste buds

Question 34

Describe circumvallate papillae.

Answer 34

Least numerous Largest lingual papillae One row of 8-12 circumvallate papillae lies just anterior to the sulcus terminalis Contain over half of the taste buds on the human tongue

Question 35

What are taste buds?

Answer 35

Small, ovoid intraepithelial organ Taste pore on the apical surface Embedded on lateral surfaces of fungiform and circumvallate papillae

Question 36

What is the name of the serous salivary glands that empty into the deep groove that surrounds each circumvallate papilla?

Answer 36

von Ebner's glands

Question 37

What is the purpose of von Ebner's glands?

Answer 37

Washes food particulates from the vicinity by providing a continuous flow of fluid over the taste buds

Question 38

What enzyme do von Ebner's glands secrete and why?

Answer 38

Lipase Prevents the formation of a hydrophobic film over the taste buds

Question 39

What number of tastes buds are on the listed areas: a) Tongue b) Soft palate c) Epiglottis d) Larynx and pharynx

Answer 39

a) 5000 b) 2500 c) 900 d) 600

Question 40

What are the 3 types of cells recognised in a taste bud?

Answer 40

1. Sensory/taste receptor cells (lightly stained) 2. Supporting/sustentacular cells (darkly staining) 3. Basal cells

Question 41

What is the lifespan of the sensory and support cells of taste buds?

Answer 41

10-14 days

Question 42

What is the compostion of the posterior surface of the tongue?

Answer 42

Relatively smooth stratified squamous epithelium with underlying lymphoid tissue called the lingual tonsil

Question 43

What is Waldeyer's ring of lymphoid tissue?

Answer 43

Lingual tonsil, palatine tonsils and adenoids that guard the entrance to the gastrointestinal and respiratory tracts

Question 44

What are salivary glands?

Answer 44

Exocrine glands of the oral cavity that produce saliva

Question 45

What is saliva?

Answer 45

Hypotonic watery secretion Contains mucous, enzymes, antibodies and inorganic ions

Question 46

What is the pH of saliva?

Answer 46

6.7-6.9

Question 47

What are the principle enzymes in saliva?

Answer 47

Amylase and lysosyme

Question 48

True or False: 500-1000 mL of saliva is produced daily.

Answer 48

False, 700-1200 mL

Question 49

List the basic functions of saliva.

Answer 49

1. Protection 2. Antimicrobial activity 3. Digestion 4. Taste 5. Buffering 6. Tooth integrity

Question 50

What percentage of saliva is produced by the major salivary glands?

Answer 50

90%

Question 51

What are the major salivary glands?

Answer 51

Parotid Submandibular Sublingual

Question 52

Name the minor salivary glands.

Answer 52

Palatine Lingual

Question 53

What type of gland are major salivary glands?

Answer 53

Compound tubulo-acinar gland

Question 54

What are the components of the salivary parenchyma?

Answer 54

Serous acini Mucous acini Duct system

Question 55

True or False: Salivary glands are covered by a tough C.T. capsule with septa subdividing the gland into lobes.

Answer 55

True

Question 56

What is the difference between simple and compound ducts?

Answer 56

Simple are unbranched while compound are branched

Question 57

Salivary glands use a merocrine mechanism of secretion. Define merocrine secretion.

Answer 57

Occurs by exocytosis

Question 58

What are the secretions of serous cells like?

Answer 58

Thin and watery Contains proteins and ions

Question 59

Is a serous cell more likely to be an acinus or a tubular element?

Answer 59

More likely to form the rounded acinus

Question 60

What is the duct system for major salivary glands?

Answer 60

Intercalated ducts into striated ducts and then empty into main excretory duct

Question 61

Describe serous cells.

Answer 61

Polarised, protein-secreting cells Pyramidal with a prominent basal nucleus and extensive RER Connected by junctional complexes

Question 62

Describe mucous cells.

Answer 62

Cuboidal-columnar cells with basal nuclei and large numbers of secretory granules Stain lighter than serous cells

Question 63

What is a serous demilune?

Answer 63

A cap-like/cresent shaped arrangement of serous cells at the end of a secretory unit in mixed acini

Question 64

Why are convention preparations of mixed acini not as accurate as other methods such as rapid freezing?

Answer 64

Mucous cells swell and push serous cells aside, creating an artifact

Question 65

What are myoepithelial cells?

Answer 65

Specialised epithelial cells Contract to help expel secretions from the acini

Question 66

Where are myoepithelial cells found?

Answer 66

Inside the basal lamina of secretory units as well the initial duct system to a lesser extent

Question 67

What is the epithelium of intercalated ducts?

Answer 67

Simple cuboidal

Question 68

What is the epithelium of striated ducts?

Answer 68

Simple columnar

Question 69

What is the epithelium of excretory/interlobular ducts?

Answer 69

Pseudostratified/stratified cuboidal to stratified columnar in distal parts

Question 70

Why are striated ducts striated?

Answer 70

Membrane infoldings of the basal lamina with mitochondria

Question 71

What classification of gland is the parotid gland?

Answer 71

Compound acinar gland with secretory portions with exclusively serous cells

Question 72

Describe the structure of the parotid gland.

Answer 72

Divided into several lobules Outer capsule with radiating septa carrying vessels and excretory ducts

Question 73

What type of gland is the submandibular gland?

Answer 73

Mixed gland with secretory units often being seromucous (but pure versions of each also present)

Question 74

How do mucigen and zymogen (enzyme-containing) granules appear in H&E staining?

Answer 74

Mucigen stain poorly while zymogen stains strongly

Question 75

Compare the nuclei of mucous vs serous cells.

Answer 75

Mucous: flattened and condensed on the basement membrane Serous: rounded and central

Question 76

True or False: Serous cells predominate within the sublingual gland with only a small number of mucous cells.

Answer 76

False, mucous cells are more numerous

Question 77

What are the amount of serous vs mucous in each major salivary gland?

Answer 77

Parotid: entirely serous Submandibular: 2/3 serous Sublingual: about 1/3 serous

Question 78

What are the minor salivary glands and their location?

Answer 78

1. Lingual - posterior dorsum of the tongue 2. Minor sublingual - lower surface of tongue 3. Labial - inner lip 4. Palatine - soft and post. hard palate submucosa 5. Buccal - cheek submucosa lining

Question 79

What type of secretion is typical in minor salivary glands?

Answer 79

Mucous