[7] Histology of the GI Tract, and Glands Flashcards
Entrance to the GI System
Oral Cavity
Which lingual papillae have no taste buds?
Filiform
Which lingual papillae are the most abundant?
Filiform
Where are Von Ebner glands found?
Circumvallate Papillae
Function: Von Ebner Glands
Lubrication
4 Main Layers
- Mucosa
- Submucosa
- Muscularis Externa
- Adventitia/Serosa
[Esophagus Layers]
Describe: Mucosa
Stratified squamous, thinly keratinized epithelium
[Esophagus Layers]
Describe: Submucosa
- With blood vessels, lymphatic vessels and nerves (Meissner’s plexus)
- Contain numerous esophageal glands proper for lubrication of food
[Esophagus Layers]
Describe: Muscularis Externa
Upper 1/3: Purely striated
Middle 1/3: Mixed
Lower 1/3: Purely smooth muscle
[Stomach Layers]
Epithelium changes from what to what?
Stratified Squamous -> Simple Columnar
[Stomach Layers]
In what layer are glands only found?
Mucosa
[Stomach Layers]
Where do glands pour their secretions?
Depressions in rugae called gastric pits / foveolae
What produces Pepsinogen?
Chief Cells
What cells produces HCl acid?
Parietal Cells
What are the most numerous glands of the gastric mucosa?
Chief Cells
What are the most conspicuous glands of the gastric mucosa?
Parietal Cells
Function: Gastric Intrinsic Factor
Vitamin B12
Types of Enteroendocrine Cells and Function
- G Cell: Gastrin (+ HCl Production)
- EC Cell: Serotonin
- D Cell: Somatostatin
- A Cell: Enteroglucagon
- ECL Cell: Histamine
3 Layers of Stomach Muscularis
- Circular: Complete
- Oblique: Incomplete
- Longitudinal: Incomplete
How are parietal/chief cells replaced?
Mitosis / Stem Cells
Define: Mucosal Restitution
Undamaged cells from bottom of gastric pits migrate to denuded basal lamina
Surface Modifications of the Small Intestine
- Plicae Circularis/Valves of Kerckring
- Villi
- Microvilli
- Crypts of Lieberkuhn
- Absorptive Cell
Glands found in the Intestine
- Goblet Cells
2. APUD Cells
Function: Paneth Cell
Create lysozymes and IgA (Immunologic)
Exclusive to small intestine
Muscularis Mucosae is composed of?
Smooth Muscle Cells
[Brunner’s Glands]
Location
Function
L: Duodenum
F: Secrete alkaline mucus and EGF
Explain Peyer’s Patches role in neglected typhoid fever
They can hypertrophy and outgrow their blood sources causing necrosis
[Cecum and Colon]
Describe:
- Mucosa
- Plicae Circularis
- Crypts
- Paneth Cells
- Goblet Cells
- Smooth Mucosa
- ( - ) Plicae Circularis
- Numerous Crypts
- ( - ) Paneth Cells
- More Goblet Cells
[Anus]
Epithelium changes from what to what?
From columnar -> stratified squamous epithelium
Differentiate minor and major salivary glands via opening
Minor: Open directly to mucosa via short ducts
Major: Open to the oral cavity via branching ducts
Pathway of Pancreatic Duct System
Acinus -> Intercalated Duct -> Intralobular Duct -> Interlobular Duct -> Pancreatic Duct
What is the main pancreatic duct?
What is the accessory duct?
Main: Wirsung
Accessory: Santorini
Where are exocrine glands located?
What about endocrine glands?
Exocrine: Apical
Endocrine: Basal (Close to blood)
[T/F]
There are striated ducts in the pancreatic duct system.
F
