Oral Cavity & Esophagus Histology - Shaw

Question 1

What are the four layers of the GI?

Answer 1

1. Mucosa: epithelium; basement membrane; lamina propria; muscularis mucosae
2. Submucosa: connective tissue
3. Supporting wall: smooth or skeletal muscle; bone; cartilage
4. Adventitia or serosa

Question 2

What are the three surface features of the lip?

Answer 2

Cutaneous area
Red area
Oral mucosa

Question 3

What is the supporting wall of the lip?

Answer 3

orbicularis oris muscle

Question 4

What are the important layers of the cheek?

Answer 4

Mucosa and submucosa: similar to lip
-Elastic tissue in submucosa helps reduce chomping on the mucosa

Supporting wall = Buccinator muscle

Question 5

What are the important layers of the hard palate?

Answer 5

Mucosa:
-Stratified squamous keratinizing epithelium

Submucosa:

• Absent in midline
• Anterior 1/3 has much fat
• Posterior 2/3 has many mucous glands

Supporting wall = Bone

Question 6

What are the important layers of the soft palate?

Answer 6

Mucosa:

• Stratified squamous keratinizing epithelium on oral side
• Pseudostratified columnar ciliated epithelium on nasal side

Submucosa
-Mixed glands

Supporting wall = Skeletal muscle and connective tissue

Question 7

What kind of tissue is the ventral surface of the tonuge composed of?

Answer 7

Stratified squamous non-keratnizing epithelium

Mixed glands beneath epithelium

Question 8

What kind of tissue is the dorsal surface of the tongue composed of?

Answer 8

Mucosa

• Stratified squamous keratinizing epithelium
• Lamina propria connects to underlying c.t.
• Modified to form various papillae
• Serous glands beneath circumvallate papillae
• Mucous glands empty into tonsillar crypts

Supporting wall: skeletal muscle (3 planes)

Question 9

What is the nerve supply of the tongue?

Answer 9

Anterior 2/3 by cranial nerves V & VII

Posterior 1/3 by cranial nerves IX and X

Question 10

What are the four types of tongue papillae?

Answer 10

1. Filiform
2. Fungiform
3. Circumvallate (“V” shape)
4. Foliate (lateral sides)

Question 11

Filiform Papillae

shape?
keratinized?

Answer 11

Occur in parallel rows across tongue

Keratinization most obvious at tip of papillae

***Most numerous type

Question 12

Fungiform Papillae

shape?
keratinized?
innervation?

Answer 12

• Fewer in number; more numerous towards tip of tongue
• Club shaped
• May have slight reddish tint due to underlying vascularization
• Some taste buds in epithelium
• Supplied by cranial nerve VII

Question 13

Circumvallate Papillae

taste buds?
innervation?

Answer 13

• Adjacent to sulcus terminalis
• 7-12 in number
• Each papilla is surrounded by a deep trench or moat
• Taste buds numerous in sides of papillae
• Supplied by cranial nerve IX
• Serous glands of von Ebner empty into trench

Question 14

Foliate Papillae

Answer 14

• Poorly developed in humans

- Taste buds are present

Question 15

What papillae are associated with taste buds?

Answer 15

circumvallate, fungiform, and foliate papillae

Question 16

What are the three types of cells that form taste buds?

Answer 16

• Sustentacular (supporting) cells
• Taste receptor cells
• Basal cells (give rise to other 2 types)

Question 17

What do taste buds do?

Answer 17

• Perceive modalities of taste (salt, sweet, sour, bitter, umami)
• Constant turnover occurs
• Nerve supply dependent

Question 18

What are the major salivary glands?

Answer 18

Parotid gland
Submandibular gland
Sublingual gland

Question 19

What are the minor salivary glands?

Answer 19

Mucous-serous glands in lamina propria and submucosa of oral cavity

Question 20

What is the composition of saliva?

Answer 20

Water, cellular & bacterial debris, leukocytes, salts, salivary amylase, mucus, secretory IgA, desquamated epithelial cells

Produce => 1000-1500 ml saliva/day in humans!

Question 21

What is the structure of major salivary glands?

Answer 21

Connective tissue capsule (capsule of parotid is especially pronounced)

Lobes and lobules

Question 22

What type of ducts are we supposed to be able to identify?

Answer 22

• Excretory duct
• Striated duct (intralobular or secretory duct)
• Intercalated duct
• Alveolus: Mucous, Serous, Demilunes

Question 23

What are myoepithelial cells?

Answer 23

• Specialized smooth muscle cells
• Between serous (secretory) and/or mucous cells and basement membrane
• Assist in discharge from the secretory cells
• Associated with both the secretory unit and the beginning of the intercalated duct

Question 24

What are the unique features of the Parotid Gland?

Answer 24

• Prominent connective tissue capsule with c.t. separating lobes & lobules
• Fat cells and fatty tissue common
• Striated and intercalated ducts prominent
• Acini almost 100% serous

Question 25

What are the unique features of the Submandibular Gland?

Answer 25

• Connnective tissue capsule present but not conspicuous
• Striated ducts well defined
• Intercalated ducts scarce
• Acini are 10-25% mucous & the rest serous
• Mucous alveoli frequently capped with serous demilunes

Question 26

What are the unique features of the Sublingual Gland?

Answer 26

• Connective tissue capsule indistinct
• Connective tissue septae are present within the gland
• Excretory ducts prominent
• Striated ducts not prevalent
• Intercalated ducts non-existent
• Acini 75% mucous with serous demilunes

Question 27

What are the four layers of the Esophagus?

Answer 27

Mucosa (epithelium, lamina propria, mm)
-Mucous (cardiac) glands in upper & lower 1/3

Submucosa
-Mucous glands in middle 1/3; submucosal nerve plexi; larger blood vessels & lymphatics

Muscularis externa
-Skeletal muscle transitions to smooth muscle; myenteric nerve plexi

Adventitia

Question 28

What is the function of saliva?

Answer 28

• Lubrication & moistening of buccal mucosa and lips
• Washes mouth of cellular and food debris
• Moistens food for easy swallowing
• Moistens food for tasting
• Enzymes may initiate digestion of the food