Oral Cavity Histology

Question 1

What are the two main parts of the oral cavity?

Answer 1

• vestibule: space between lip, cheeks, and teeth

* oral cavity proper: hard and soft palates, tongue, floor of mouth, and entrance to oropharynx.

Question 2

What are the 3 major paired salivary glands that have ducts that open into the oral cavity?!

Answer 2

parotid, submandibular, and sublinqual

Question 3

Mucosa in the oral cavity consists of what?

Answer 3

1) epithelium
2) lamina propria

NOTE: there are 3 kinds of mucosa in the oral cavity

Question 4

What are the three types of mucosa found in the oral cavity?

Answer 4

1) masticatory mucosa
2) specialized mucosa
3) lining mucosa

Question 5

Where is masticatory mucosa found and what kind of epithelium does it have?

Answer 5

found on gingiva and hard palate – has SSE Keratinized or SSE parakeratinized epithelium

Question 6

Where is specialized mucosa found and what kind of epithelium does it have?

Answer 6

found on dorsum of the tongue (called specialized because of its abundant papillae)

SSE keratinized epithelium predominantly

Question 7

Where is lining mucosa found and what kind of epithelium does it have?

Answer 7

found on everything that’s not masticatory or specialized, (i.e., lips, cheeks, floor of mouth, alveolar region, and soft palate)

has SSE nonkeratinized epithelium

Question 8

Why does lining epithelium have sparse, short papillae?

Answer 8

so mucosa can adapt to underlying skeletal muscle

Question 9

Why does the epithelium of masticatory mucosa have deep papillae from the underlying laminar propria?

Answer 9

they strengthen mucosal stability

Question 10

What are the four types of lingual papillaefound on the specialized mucosa?

Answer 10

1) filiform papillae- smallest and most numerous - over the entire anterior 2/3- in rows, highly keratinized
2) fungiform papillae- scattered among the filiform - mushroom shaped - bear taste buds- not well developed in human, keratinized in herbivores
3) Circumvallate papillae- castle and moat arrangement, 8-12 in a row dividing the anterior 2/3 and post 1/3 of the tongue- large and dome shaped surrounded by moat- bear taste buds. Have minor salivary gland (von Ebner) that washes foods through and out of the moat.
4) foliate papillae- parallel low ridges on the lateral edge- bear taste buds

Question 11

What kind of epithelium does filiform papillae have?

Answer 11

SSE -K

Question 12

What kind of epithelium does fungiform papillae have?

Answer 12

may be keratinized

Question 13

Which of the lingual papillae of the specialized mucosa does not have taste buds?

Answer 13

only filiform papillae (specialized, circumvallate, and foliate papillae do have taste buds)

Question 14

What does herpes simplex 1 do to oral cavity epithelium?

Answer 14

Viral infections with herpes simplex 1 cause death of infected epithelial cells that can lead to vesicular or ulcerating lesions of the oral mucosa or skin near the mouth. In the oral cavity such areas are called canker sores, and on the skin they are usually called cold sores or fever blisters. Such lesions, often painful and clustered, occur when the immune defenses are weakened by emotional stress, fever, illness, or local skin damage, allowing the virus, present in the local nerves, to move into the epithelial cells.

Question 15

Taste buds on fungiform papillae are generally on what side of the tongue?

Answer 15

the dorsal surface

Question 16

What is the Foramen cecum?

Answer 16

the remnant of the site from which an evagination of the floor of the embryonic pharynx occurred to form the thyroid gland

Question 17

Where are the taste buds on Vallate (gustatory) papillae located?

Answer 17

on the lateral surface, and open into the moat

Question 18

What are the five known tastes?

Answer 18

sour, bitter, sweet, salt, umami

Question 19

What is umami?

Answer 19

the taste of L-glutamate in monosodium glutamate and asparagus

Question 20

The ability to taste bitterness is generally limited to which portion of the tongue?

Answer 20

the back of the tongue (all other taste buds are distributed all over the tongue)

NOTE: the tongue has ~2000 taste buds

Question 21

T or F. taste buds are only found on the tongue

Answer 21

F. a few taste buds also exist on the roof of the mouth, posterior tongue, epiglottis, esophagus, and pharynx

Question 22

What are the three kinds of cells found in taste buds and what do they do?

Answer 22

Sensory cells- elongated, predominant, synapse w afferent nerve fiber

Supporting cells – also elongated like glial cells

Basal cells - short, stem cell for the sensory and supporting cells

Question 23

The major salivary glands are the submandibular, the parotid, and the sublingual glands. Does the oral cavity have minor glands? Where?

Answer 23

Yes, they are located in the CT of the cheek, tongue, and palate

Question 24

What are the two principal cell types in major glands in the oral cavity?

Answer 24

1) serous cells

2) mucous cells

Question 25

What do serous cells secrete?

Answer 25

watery substance with protein, amylase, and lysozyme

NOTE: they have basal basophilia, many granules in apical cytoplasm

polarized protein-secreting cells, usually pyramidal in shape, with round nuclei, well-stained RER, and apical secretory granules. Joined apically by tight and adherent junctions, serous cells form a somewhat spherical unit called an acinus (L. grape), with a very small central lumen

Question 26

What do mucous cells secrete?

Answer 26

secrete mucus (which is lost during preparation so that apical region looks empty)

NOTE: Nucleus is typically flattened at the base of the cell

Mucous cells are somewhat more columnar in shape, with more compressed basal nuclei. Mucous cells contain apical granules with hydrophilic mucins that provide lubricating properties in saliva

Question 27

What is the role of exocrine glands in the mouth?

Answer 27

produce saliva, which has digestive, lubricating, and protective functions. With a normal pH of 6.5 to 6.9, saliva also has an important buffering function and in some species is also important for evaporative cooling.

About 90% of saliva is produced by three bilateral pairs of salivary glands: the parotid, submandibular, and sublingual glands. These glands plus microscopic minor salivary glands throughout the oral mucosa produce 0.75-1.50 L of saliva daily.

Question 28

How are salivary glands organized?

Answer 28

• clusters of cells are organized into acini or alveoli

Question 29

What are acini?

Answer 29

a small sac-like cavity in a gland, surrounded by secretory cells

Question 30

What are alveoli in salivary glands?

Answer 30

a small cavity, pit, or hollow

Question 31

What are the elongated contractile cells that surround the epithelial basal lamina of salivary glands?

Answer 31

myoepithelial cells (secretion by acini cells is extruded by contraction of myoepithelial cells)

Question 32

How are salivary gland ducts organized?

Answer 32

• intercalated ducts originate from acini, secrete and absorb, (they have simple cuboidal epithelium)
• striated ducts – simple cuboidal to simple columnar cells, striations caused by basal plasma membrane

Question 33

What are some possible causes of Inadequate saliva production, leading to dry mouth or xerostomia?

Answer 33

various factors affecting the major salivary glands, such as mumps viral infection, radiation of the glands, or the normal side effect of drugs such as antihistamines.

Question 34

Which part of salivary gland duct systems are involved in modification of secretions?

Answer 34

intercalated ducts and striated ducts (interlobular ducts are just conduits and are not involved in modifying the secretion)

Question 35

parotid glands are composed purely of what?

Answer 35

serous acini

Question 36

In mixed glands (like the submandibular gland) the mucous cells exist as what?

Answer 36

either purely mucous acini or as mixed acini in which the serous cells form a cap called serous demilune

NOTE: there is some evidence that the serous demilune is an artifact produced during slide prep as the mucous cells swell and squeeze the serous cells to the periphery.

Question 37

T or F. Saliva is a product of submandibuluar glands?

Answer 37

F. it is a mixture of the secretions of all three major glands and it’s composition/contents changes frequently

Question 38

What buffers the saliva content in the oral cavity?

Answer 38

bicarbonate ions

Question 39

What are the major functions of saliva? (7 things)

Answer 39

• contains digestive enzymes (amylase, lipase) to begin digestion
• help protect mucosa by washing away harmful substances
• has proteins that provide protective film for teeth
• provides calcium and phosphate that is important for mineralization of teeth
• lubricates oral cavity for easy movement
• provides medium for dissolved food to stimulate taste buds
• has antibodies for immune defense

Question 40

What are the antibodies found in saliva?

Where are they synthesized?

Answer 40

(salivary immunoglobulin A). IgA is synthesized by plasma cells in the connective tissue surrounding secretory acini. Both dimeric and monomeric forms are released into CT. Acini cells synthesize a glycoprotein on cell surface that serve as receptor for dimeric IgA. When dimeric IgA binds to the receptor, secretory IgA complex thus formed and internalized.