Oral Cavity & Esophagus Histology Flashcards
Components of Digestive System:
- Oral cavity
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Pancreas; Liver; Gallbladder
What are the four structural layers of the Digestive system?
- Mucosa
- Submucosa
- Supporting wall
- Adventitia or Serosa
What is the mucosa made up of?
Epithelium, basement membrane, lamina propria, muscularis mucosae
What is the submucosa made up of?
Connective tissue
What is the Supporting wall made up of?
Smooth or skeletal muscle, bone, cartilage
What ar the components of the lip?
- Surface features
- -Cutaneous area
- -Red area
- -Oral mucosa
- Submucosa ?
- Supporting wall: orbicular oris muscle
What are the components of the cheek?
- Mucosa and submucosa: similar to lip
- -Elastic tissue in submucosa helps reduce chomping on the mucosa
- Supporting wall
- -Buccinator muscle
Components of the Hard Palate:
- 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
Components of the Soft Palate:
- 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
What makes up the ventral surface of the tongue?
- Stratified squamous non-keratinizing epithelium
- Mixed glands beneath epithelium
What makes up the Dorsal surface of the tongue?
- 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)
What is the nerve supply to the tongue?
- Anterior 2/3 by cranial nerves V & VII
- Posterior 1/3 by cranial nerves IX and X
What are the four Tongue Papillae?
- Filiform
- Fungiform
- Circumvallate
- Foliate
What is the Filiform Papillae?
- Most numerous type
- V shaped structure with keratin at top
- Occur in parallel rows across tongue
- Keratinization most obvious at tip of papillae
What are the Fungiform Papillae?
- 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
What nerve supplies the Fungiform Papillae?
Cranial Nerve VII
What are the Circumvallate Papillae?
- Adjacent ot sulcus terminalis
- 7-12 in number
- Each papilla is surrounded by a deep trench or moat
- Taste buds numbers in sides of papillae
- Serous glands of von Exner empty into trench
What nerve supplies the Circumvallate Papillae?
Cranial Nerve IX
What are Foliate Papillae?
- Poorly developed in humans
- Lateral sides of tongue
- Taste buds are present
What are taste buds associated with?
Circumvallate, fungiform and foliate papillae
Where are taste buds embedded?
In epithelial layer
What are three types of taste bud cells?
- Sustentacular (supporting) cells
- Taste receptor cells
- Basal cells (give rise to other 2 types)
What else should you know about taste buds?
- Perceive modalities of taste (salt, sweet, sour, bitter, umami)
- Constant turnover occurs
- Nerve supply dependent
What are the major salivary glands?
- Parotid gland
- Submandibular gland
- Sublingual gland
What are the minor salivary glands?
-Mucous-serous glands in lamina propria and submucosa of oral cavity
What is the composition of Saliva?
Water, cellular & bacterial debris, leukocytes, salts, salivary amylase, mucus, secretory IgA, desquamated epithelial cells
–1000-1500 ml saliva/day in humans
What is the function of Saliva?
- 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
What is the morphology of major salivary glands?
- Connective tissue capsule (capsule of parotid is especially pronounced)
- Lobes and lobules
What ar the different ducts of the Oral cavity/Esophagus?
- Excretory duct
- Striated duct (intralobar or secretory duct)
- Intercalated duct
- Alveolus
- -Mucous
- -Serous
- -Demilunes
What are Myoepithelial Cells?
- Specialized smooth muscle cells
- Between serous 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
What is the Parotid Gland?
- 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
What is the Submandibular Gland?
- Connective 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
What is the Sublingual Gland?
- Connective tissue capsule indistinct
- Connective tissue septa are present within the gland
- Excretory ducts prominent
- Striated ducts not prevalent
- Intercalated ducts non-existent
- Acini 75 percent mucous with serous demilunes
What are the four Esophageal layers?
- Mucosa
- Submucosa
- Muscularis Externa
- Adventitia
What makes up the Mucosa of the Esophagus?
(epithelium, lamina propria, mm)
-Mucous (cardiac) glands in upper and lower 1/3
What make sup the Submucosa?
-Mucous glands in middle 1/3; submucosal nerve plexi; larger blood vessels and lymphatics
What makes up the Mucularis externa?
-Skeletal muscle transitions to smooth muscle; myenteric nerve plexi
