Histo of the Esophagus & Stomach Flashcards
What are the four layers of the GI tract?
mucosa
submucosa
muscularis externa
serosa/adventita
What are the components of the mucosal layer?
Epithelium
Lamina Propria-contains lymphatics, lymphocytes etc.
muscularis mucosae-controls mobility of mucosa glands (gastric pits)
What are the components of submucosal layer?
Dense irregular CT with neurovasculature & lymphatics
What are the components of the muscularis externa?
Two layers of smooth muscle -inner and outer layers
Contraction of the circular layer does what?
Constricts lumen
Contraction of longitudinal layer does what?
shortens the tube
What are the components of Serosa/Adventitia?
When suspended by mesentery, adventitia is covered by mesothelium forming serosa
-without mesothelium–>adventitia
Where is nonkeratinzed stratified squamous found?
(Protective) Oral cavity pharynx anal canal
Where is simple columnar epithelium (secretory)?
Mucosa packed with glands Stomach
Where is simple columnar epithelium (Absorptive)?
Mucosa arranged as villi with crypts
What is simple columnar epithelium (Absorptive/Protective)?
Mucosa arranged into closely packed glands goblet cells
What do the submuscosal plexus of meissner and myenteric plexus of auerbach regulate?
- Peristaltic contractions of muscularis externa and muscularis mucosae
- Secretory activities of the mucosal and submucosal glands
Thoracic esophagus has what kind of external layer?
adventita
Inferior to the diaphragm has what kind of external layer?
serosa
Where are cardiac esophageal glands found?
In the lamina propria of terminal esophagus
What does the upper sphincter of the esophagus do?
anatomical, swallowing reflex
What does the lower sphincter of the esophagus do?
function, prevents reflux of gastric contents
What is Barrett’s esophagus/metaplasia?
Chronic GERD Nonkeratinzed stratified squamous in transition zone–> becomes columnar mucus-secreting
What is the gastroesophageal Junction?
Transition from esophagus to stomach
Nonkeratinized stratified squamous–> simple columnar
What are the four regions of the stomach?
Cardia
Fundus
Body
Pyloric antrum
Orad Area
fundus and upper part of the body relaxes during swallowing
Caudad Area
Lower portion of the body & the antrum
Regulation of gastric emptying
What makes up a fundic (gastric) gland?
Gastric Pit
Isthmus/Neck
Gastric gland
What are hallmarks of chief cells?
- abundant RER & apical secretory (zymogen) granules
- produce gastric lipase
- peipsinogen
What are the hallmarks of parietal cells?
- Produce HCL and IF
- Usually round or pryamidal-shaped, round nucleus
- Cytoplasm is intensely eosinophilic due to increase in mitochondria
What are enteroendocrine cells?
- Epithelial cells in gastric mucosa with endocrine functions
- Secrete to help with digestive function
What is the difference between cardiac and pyloric glands?
cardiac glands are circular and pyloric glands are more tubular
