Histology Flashcards
What is the mucosa composed of?
Epithelium
Lamina propria
Muscularis mucosae
What is the lamina propria?
Loose connective tissue
What is the muscular mucosae?
Thin layer of smooth mucle
What are the layers of the GI tract wall?
Mucosa
Submucosa
Muscularis externa/propria
Serosa or adventitia
What is the submucosa?
Connective tissue
What is the muscularis externa?
2 thick layers of muscle - inner circular and outer longitudinal
When is the outer layer serosa and when is it adventitia?
Adventitia when the connective tissue surrounding the tract blends into other connective tissue
Serosa if the surface is free
What is the difference between the serosa and adventitia?
Serosa (surface is free) will have a thin covering sheet of epithelium - mesothelium
What is the oesophagus lined by?
Non-keratinised stratified squamous epithelium
What is the stomach to the anal canal lined by?
Simple columnar epithelium with goblet cells
What is different about the surface of the stomach?
Has gastric pits that end in gastric glands
Gastric glands contain parietal cells and chief cells
What do parietal cells and chief cells produce?
Parietal - HCl and intrinsic factor
Chief - pepsinogen
What is different about the surface of the whole small intestine?
Villi
Crypts of Leiberkuhn between villi
What is only present in the duodenum, and what is its function?
Brunner’s glands - secrete alkaline mucus to help neutralise acidic chyme from the stomach
Which cells are present in the villi of the small intestines, and what are their functions?
Goblet cells (mucus producing) Enterocytes (absorptive cells)
Which cells are present in the crypts of the small intestine, and what are their functions?
Paneth cells (produce bacteriostatic compounds) Stem cells
What is the structure of the wall of the colon?
Crypts
Enterocytes (absorptive) in epithelium
What is the liver covered by?
Collagenous capsule with an outer covering of simple squamous epithelium - mesothelium
What type of capillaries are sinusoids?
Discontinuous
What is the space of Disse?
The space between sinusoids and hepatocytes
What are found int he space of Disse?
Kuppfer cells (macrophages) Stellate cells
What are stellate cells?
Modified fibroblasts that store vitamin A
What type of epithelial cells are cholangiocytes?
Cuboidal
What is the structure of the gallbladder wall?
Simple columnar epithelium Basal lamina Loos connective tissue (lots of blood vessels and lymphatics) Smooth muscle coat Adventitia
What is the structure of the pancreas?
Thin collagenous capsule that is continuous with the septa that breaks the pancreas into many lobules
What type of cells is the pancreas mainly made up of?
Secretory epithelial cells
Where are the islets of Langerhans found?
Pancreas - endocrine
What type of gland is the exocrine component of the pancreas?
Acinar
Does the endocrine pancreas have ducts?
No - secretes hormones into the bloodstream
