Histo Esophagus & Stomach Flashcards
What are the 4 layers of the GI tract from lumen to superficial
Mucosa
Submucosa
Muscularis externa
Serosa/Adventitia
How do you know which organs have advantitia vs serosa?
Serosa - Intraperitoneal organs
Adventitia - Retroperitoneal
SAD PUCKER - Retroperitoneal organs Supra renal glands Aorta/Vena Cava Dudodenum (2,3,4) Pancreas Ureters Ascending/Descending Colon Kidneys Esophagus Rectum
What are the Three layers of the Mucosa?
Epithelium
Lamina Propria
Muscularis Mucosa (thin muscle layer)
What tissue is the Lamina Propria composed of and what structures does it contain?
Loose Connective Tissue
Blood Vessels
Lymph nodules
What does the Muscularis Mucosa do?
Controls mucosal glands and movement of mucosa
What tissue is the submucosa composed of and what structures does it contain?
Submucosa is composed of dense irregular connective tissue
Contains neurovasculature
Lymphatics
Contains glands in the Esophagus and Duodenum
In which organs will you find glands in the Submucosa?
Esophagus and duodenum
What is the structural difference between the Serosa and Adventitia?
Serosa has an adventitia with a mesothelium layer on top
Adventitia is alone in retroperitoneal organs (no mesothelium)
What type of cell is typically epithelial in the GI tract?
Simple columnar
Does the esophagus have adventitia or serosa?
Esophagus has both
Thoracic esophagus has adventitia
Abdominal esophagus (below diaphragm) has serosa
What are the two glands found in the esophagus?
Cardiac esophageal Glands - Found in the Lamina Propria (mucosa) of the terminal esophagus (near cardiac of the stomach)
Submucosal Glands - Small lobules with mucous and serous cell types drained by a single duct
Muscularis Mucosa is only present in some of the esophagus, where?
Lower segments
What cell type makes up most of the epithelium of the esophagus?
Non-keratinized stratified squamous
How does the muscularis vary by segments of teh esophagus?
Upper third = striated muscle
Middle third = striated and smooth muscle
Lower third = smooth muscle
How does the epithelium transition from the Esophagus to the stomach?
Stratified Squamous –> simple columnar
Gastric epithelium is glandular with pits and glands
In chronic GERD (Barrett’s esophagus) what happens to the Esophageal epithelium?
Changes from Stratified squamous to columnar mucus-secreting/glandular cells
What are the layers of muscle in the muscularis of the stomach?
Oblique, Circular, Longitudinal
What are the names of the glands of the stomach, where are they found?
Cardiac glands, Gastric glands, Pyloric glands
(Gastric Glands = Fundus glands)
Named according to location in the stomach
Located in the Lamina Propria
Describe the Gastric Glands
Aka Fundic Glands
Simple branched tubular glands
Extend from bottom of gastric pits to muscularis
Have 3 parts:
- Isthmus (between gastric pit and gland below) - site of stem cell niche
- Neck - Narrow and long segment
- Fundus - Shorter and wider segment; base
FOUND ANYWHERE IN THE STOMACH PYLORIC AND CARDIAC GLANDS ARE ABSENT
How to recognize mucous neck cell?
Mucous does not absorb stain, cells appear white/clearer
What types are cells are found in the neck of the Gastric Gland?
Mucous neck cells Enteroendocrine cells (G cells - secrete gastrin) Parietal cells (secrete acid)
What types of cells are found in the Fundus of the Gastric glands?
Enteroendocrine cells (G cells - secrete gastrin into blood) Chief cells (secrete pepsinogen, for protein digestion) Some parietal cells (acid secretion)
What cells are found in the Isthmus of the Gastric Gland?
Dividing stem cells
How do Chief cells appear on a slide?
Stained darkly red due to presence of zymogen (pepsinogen) granules.
