Gut Histology Flashcards
What are the 4 layers in the general structure of the gut?
Mucosa
Submucosa
Muscularis
Adventitia
What is the deepest layer in gut histology?
Mucosa
What does the mucosa of the gut made up of?
Epithelium layer
Lamina propria layer- containing blood vessels, lymphatics, and immune cells
What layer of the gut is superficial to the mucosa?
Submucosa
What is the submucosa of the gut made up of?
Made up of fibroblasts,collagen, and an extracellular matrix
Contains vessels, lymphatic tissue, nerves, glands
What layer of the gut is superficial to the submucosa?
Muscularis externa
What is muscularis externa made up of?
2-3 Layers of smooth muscle
- Circular muscle, longitudinal muscle and nerves
- responsible for the peristalsis of the gut
What is peristalsis?
Rhythmic contractions of the gut to push food through the digestive system
What is the most superficial layer to the gut?
Adventitia/serosa
What is the adventitia/serosa of the gut made up of?
Outer layer of fibroblasts,collagen and some adipocytes
What type of epithelium lines the oesophagus?
Stratified squamous epithelium
How does the epithelium structure of the eosophagus relate to its function?
This type of epithelium protects against friction from passing food by shedding the layers closest to the lumen
What is the function of the external muscle layer of the gut?
The muscle layers work together to produce peristalsis and move food along the oesophagus to the stomach
What type of muscle is found in the muscularis externa of the oesophagus wall?
Superior 1/3-skeletal muscle
Middle 1/3- mix of skeletal and smooth muscle
Inferior 1/3-smooth muscle
How does the epithelium change at the gastro-oesophageal junction?
Sharp transition from stratified squamous epithelium to columnar epithelium
What is the clinical significnace of the change in epithelium at the gastro-oesophageal junction?
Risk of disease due to exposure of a cell type to an environment that it is not suited for e.g stratified squamous epithelium exposed to stomach acid
What type of epithelium is found in the stomach? What doe these cells secrete and what is the function of this?
- Simple columnar epithelium
- Secretes mucus to pretect the epithelial lining from autodigestion ( being digested by the stomach acid)
What is the name given to the folds within the stomach and what is the function of these folds?
Gastric fold or rugae
-allows for the expansion of the stomach after consumption of foods and liquids
What are the crypts of lieberkukn?
Tubular glands which are found between the villi
-many important cells reside in the crypts such as stem cell that replenish the epithelial cells further up the villi
Where are the crypts of lieberkukn found?
Located between the villi and intestinal epithelium
What are Brunner glands?
Glands that secrete an alkalie fluid into the duodeum to protect it from the acid chyme of the stomach
What layer of gut histology are the brunner glands found?
Located in the mucosa
What are Peyer’s patches?
Small masses of lymphatic tissue found throughout the ileum. Important in immune surveillance
What layer of gut histology are the Peyer’s patches found?
Located in the mucosa and extend into the submucosa
