GI Tract Microanatomy Flashcards
What is the inner lining of the GI tract called?
Mucosa
What is the support layer of the GI tract called?
Submucosa
What is the muscle layer of the GI tract called?
Muscularis externa/propria
What is the outer wrapping of the GI tract called?
Adventitia/serosa
Name the 4 layers of the GI tract from lumen outwards
Mucosa
Submucosa
Muscularis externa/propria
Adventitia/serosa
What 4 things make up the mucosa?
Epithelium, basement membrane, lamina propria, muscularis mucosa
What is the role of the lamina propria?
Supports the epithelium structurally and nutritionally
What type of epithelium lines the oral cavity, pharynx, oesophagus and anal canal?
Protective
Stratified squamous, non keratinising
What type of epithelium lines the stomach?
Secretory
Simple or branched tubular glands
Describe some features of the epithelium of the small intestine
Absorptive
Villi and crypts lines by columnar cells called enterocytes
Goblet cells producing mucus
Describe some features of the epithelium of the large intestine
Absorptive and protective
High number of goblet cells for lubrication
Presence of enterocytes
What is the submucosa made up of?
Connective tissue, blood vessels, lymphatics and nerves
Some glands
Submucosal (Meissner’s) plexus
What does the submucosal plexus innervate?
Glands
Muscularis mucosa
What is the muscularis externa/propria made up of?
Smooth muscle
Myenteric (Auerbach’s) plexus
What process does the myenteric plexus modulate?
Peristalsis
What is adventitia?
The outer wall of the gut tube, made up of a thin layer of connective tissue
What is serosa and where is it associated with?
A serous membrane covering the GI tract
Peritoneum
What kind of epithelium makes up a serous membrane?
Squamous epithelial cells secreting a small amount of fluid
What is a sphincter?
Thickening of the smooth muscle in the GI tract
Name the 4 sphincters of the GI tract
Oesophageogastric
Pyloric
Ileocaecal
Internal anal