GIT Flashcards
Layers of Digestive Tract (from lumen outwards)- Mucosa- Submucosa- Muscularis externa- Serosa or adventitia
- 3 parts. Epithelium, which sits on a basal lamina. Lamina proporia, which is loose connective tissue. Muscularis mucosae, which is a thin layer of smooth muscle.- Loose connective tissue- Two thick layers of smooth muscle. An inner circular layer and an outer longitudinal layer- Outer layer of connective tissue. Either suspends the digestive tract or attaches it to other organs.
What is:- Displayed in the image- Highlighted by the arrows
- General digestive tract architecture- As shown
What is:- Shown in the picture
- Oesophagus
What is:- The major structure shown in the picutre- Indicated by the arrows
- Oesophagus- As shown
Gastro-oesophageal junction- What happens
- Abrupt transition from the stratified squamous epithelium of the stomach to the columnar epithelium of the cardia of the stomach.
Gastric pits- What are they?- What’s in them?- What’s the lining like?- Ithmus, neck, base
- Holes in the fuzzy surface of the stomach- 1-7 gastric glands. Lined by surface mucous cells.- Simple columnar with surface mucous cells - like the stomach itself.- Mostly parietal cells (produce HCl).Mostly neck mucous cells and stem cells (produce pepsinogen). Mostly chief cells with some parietal and neuroendocrine cells.
What is:- Shown in the picture
- Gastric glands
Gastric pits in the…- Cardia- Body- Pylorus
- Deep pits which branch into tortuous glands- Shallow pits with long, straight glands- Deep pits which are branched and coiled at a higher density than the cardia
What is:- Shown in the picture
- Cardia
What is:- Shown in the picture
- Body of Stomach
What is:- Shown in the picture
- Pylorus
What is:- Shown in the picture- Indicated by the letters
- Gastroduodenal junction- As shown
Crypts of Lieberkuhn- What are they?
- Pits “drilling” downwards between the villi
Regions of the small intestine- Duodenum- Jejunum- Ileum
- Has brunner’s glands in the submucosa- Tallest villi located on the circular folds (plicae circularis) of mucosa and submucosa.- Shorter villi and peyer’s patches which are aggregations of lymphoid follicles. They are found on the submucosa and sometimes the lamina proporia.
Cells in small intestinal epithelium- Enterocytes- Goblet cells- Panet cells- Neuroendocrine cells- Stem cells
- Most numerous, tall columnar cells with brush border and are the principle absorptive cells- Produce mucin to protect epithelium and lubricate passage of material- Found at the base of the crypts of lieberkuhn, and have a defensive function- Produce hormones which help with the control of secretion and motility- At the base of the crypts - they divide to replenish epithelium
