Histology of the Nasal and Oral Cavities

Question 1

Respiratory epithelium:
Type:
Hallmark:

Answer 1

Pseudostratified columnar ciliated epithelium
Hallmark: Cillia, goblet cells (release mucous to coat the epithelium), thick basement membrane
Non ciliated basal cells have stem cells and will repopulate

Question 2

Lamina propia:

Answer 2

Tissue underlying the respiratory epithelium

Vascular and has capillary loops

Question 3

Nasal cavities (respiratory epithelium)
Location:
3 regions

Answer 3

-Either side of the nasal septum
Nasal vestibule (just inside the nostrils and lined with skin) 
Respiratory region (inferior 2/3 of the cavity, lined with respiratory mucosa 
Olfactory region ( apex/upper 1/3, and lined with specialized olfactory mucosa)

Question 4

*Function of the nasal cavity:

Answer 4

Adjust temp and humidity of inspired air

Enhanced by large surface area provided by the conchae

Question 5

Paranasal sinus:

Function:

Answer 5

Air filled spaces in the nasal cavity, lined with respiratory epithelium
Communicates with nasal cavities via openings, mucus produced by sinus drain into the cavities via cilia
Susceptible to infection

Question 6

Nasal vestibule of the nasal cavity will have ….

Respiratory region of the the nasal cavity will have …

Answer 6

Keratinized stratified squamous epithelium (Skin)

Pseudostratified columnar ciliated epithelium

Question 7

*Olfactory mucosa
Location:
Hallmark:
Function:

Answer 7

Location: upper part of the nasal cavity so it’s close to the brain and easier to reach by CN I
Hallmark: thicker pseudostratified ciliated columnar epithelium (10 cm), thinner basement membrane and
*No goblet cells (has glands instead that secrete mucous that line the tissue)

Question 8

Olfactory cells in the olfactory epithelium:

Features:

Answer 8

Cells that have singular dendrites that spread out around the epithelium to catch odorant molecules (have GPCR receptors in the brain that relay info to the brain)

Question 9

*Layers of the olfactory epithelium:
Basal cells:
Brush cells:
Supporting/sustentacular cells:

Answer 9

• stem cells for olfactory receptor and surrounding cells
• ciliated, columnar epithelial cells
• provide mechanical and metabolic support to olfactory receptor cells (because they’re cranky)

Question 10

Oral cavity:
Type
3 regions

Answer 10

Stratified squamous type with varying keratinization, Lined by protective mucous membrane (oral mucosa)
-Lining, masticatory and specialized mucosa

Question 11

Oral mucosa

supported by? Layers?

Answer 11

supported by dense collagenous tissue (lamina propria)

Layers of the oral lamina propria:
Papillary layer: superficial, loose CT with neurovasculature
Dense layer: deep, dense irregular CT with large amount of fibers
Submucosal layer: present depends on location, loose CT, adipose tissue and salivary glands

Question 12

Masticatory mucosa:
Type
Location

Answer 12

-keratinized and/or parakeratinized stratified squamous epithelium
Hard palate, gingiva and dorsal surface of the tongue

Question 13

Features of masticatory mucosa:

Answer 13

Lots of rete ridges (epithelial extensions) and papillae

Thin or absent submucosa

Question 14

Lining mucosa
Type
Location
Hallmark:

Answer 14

• Nonkeratinized stratified squamous epithelium, can be parakeratinized in selected regions
• lips, cheeks, alveolar mucosal surface, floor of mouth, inferior tongue and soft palate
• Fewer rete ridges and connect tissue papillae and has distinct submucosa, thicker than keratinized epithelium

Question 15

3 layers of the lining muscosa:

Answer 15

Stratum basale (single layer of cells on the basal lamina)
Stratum spinosum: several cells thick
Stratum superficiale: most superficial, surface layer of the mucosa

Question 16

Specialized mucosa:
Location:
Type:
Function:

Answer 16

• Dorsal surface of tongue
• Masticatory and specialized mucosa of tongue is keratinized stratified squamous and contains the lingual papillae and taste buds responsible for gustation

Question 17

Lingual papilla:

Answer 17

Small, elevated structures in the specialized mucosa (some are associated with taste buds)
-made of keratinized epithelium with lamina propria

Question 18

Filiform papillae:
Function:
Hallmark:

Answer 18

Moves food toward pharynx for swallowing and give the surface of tongue velvety texture
Hallmark: pointed cone, no associated taste buds

Question 19

Foliate papillae:
Hallmark:
Function:

Answer 19

Hallmark: vertical ridges on lateral surface of tongue in posterior regions, associated with taste buds so they help provide taste sensation

Question 20

Fungiform papillae:
Location:
Hallmark:

Answer 20

Found in dorsal surface of the tongue
Provide taste sensation
Hallmark:

Question 21

Circumvallate Papillae:

Hallmark:

Answer 21

Hallmark: mushroom shaped structures anterior to sulcus terminales, surrounded by trench and has lots of taste buds

Question 22

Taste buds:
Location:
Hallmark:
Function:

Answer 22

-Tongue, glossopalatine arch, soft palate, posterior epiglottis and posterior wall of phayrnx
-Hallmark: barrel shaped, made up of spindle looking cells that extend from the basement membrane
-5 tastes: sweet, salty, sour, bitter and umami
Each taste bud has all receptors but concentrate on 2/5 of these tastes

Question 23

Neuroepithelial (sensory) cells:

Answer 23

Elongated cells extending a microvilli from the basal lamina to the taste pore, and synapse with afferent sensory neurons of CN VII, IX and X

Question 24

Supporting and basal cells:

Answer 24

Supporting: elongated cells that contain a microvilli extending to the taste pore but does not synapse with the nerve cells
Basal cells: near the basal lamina, contains stem cells for the neuroepithelial and supporting cells

Question 25

Tonsils:
Hallmark:
Location:
Function:

Answer 25

Hallmark: large irregular masses of lymphoid tissue
Mucosa of posterior cavity, oropharynx and nasopharynx
Protect against inhaled or ingested substances

Question 26

Palatine tonsil:

Answer 26

Hallmark: Lined with nonkeratinized stratified squamous epithelium populated with lymphocytes, deep invaginations called tonsillar crypts, capsule is made of dense connective tissue

Question 27

Pharyngeal tonsil:
Hallmark:
Type:
Location:

Answer 27

Singular structure, thin underlying capsule with shallow invaginations (no crypts)
Covered with pseudostratified columnar ciliated epithelium
Posterior wall of nasopharynx

Question 28

Lingual tonsil:
Hallmark:
Type:
Location:

Answer 28

-lacks a capsule, has crypts and has germinal centers
Stratified squamous epithelium
-base of the tongue

Question 29

Teeth:
Parts:

Answer 29

Crown and root. Crown projects in the oral cavity and protected with enamel. Root is embedded in the alveolar ridge of alveolus (tooth socket)

Question 30

Composition of teeth:

Answer 30

Dentin (makes up bulk of tooth), enclosing the pulp chamber with the pulp
Root is within a thin layer of cementum

Question 31

Dentin:
Hallmark:
Composition:

Answer 31

Calcified organic matrix similar to bone, has dentinal tubules (parallel tubes radiating to the periphery of the dentin)
Calcium hydroxyapatite crystals

Question 32

Enamel:
Hallmark:

Answer 32

Translucent with parallel enamel rods (prisms) of calcium hydroxyapatite, cemented with interprismatic material, has diagonal lines
Covers the dentin

Question 33

Cementum:

Answer 33

Calcified structures where tooth/periodontal ligament is anchored
Covers the dentin at the root and is thicker towards the apex of the root

Question 34

Pulp:
Type:
Function:

Answer 34

• loose mesenchymal CT of collagen, fibroblasts and mesenchyme, neurovascularized
• Provides nutrition to dentin and form reactive dentin due to chronic injury

Question 35

Peridontium:

Consists of:

Answer 35

Cementum, periodontal ligament (PDL), alveolar bone and gingiva

Question 36

PDL (periodontal ligament)

Answer 36

Inserts into the cementum and alveolar bone that lines the alveolus
Consists of collagen fibers