Digestive Tract Flashcards
Epithelium of oral cavity, oropharynx and laryngopharynx
Stratified non-keratinised squamous epithelium
Epithelium of nasal cavity and nasopharynx
Respiratory epithelium
Digestive tract 4 main layers
Mucosa, submuscosa, muscualris externa and serosa or adventitia
What are the 3 layers of the muscosa
Epithelium, lamina propria and muscularis mucosae
Mucosa epithelium
Sits on a basal lamina
Mucosa lamina propria
Loose connective tissue
Mucosa muscularis muscosae
Thin layer of smooth muscle
Submucosa
Loose connective tissue
Muscularis externa
Two thick layers of smooth muscle, an inner circular layer and an outer longitudinal layer
Serosa
Outer layer of connective tissue that either suspends the digestive tract or attaches it to other organs
Gastro-oesophageal junction
Abrupt transition from stratified squamous epithelium to simple columnar epithelium
Mucosa of the stomach is made up of
Gastric pits and gastric glands
Cells of the gastric gland
Isthumus - Parietal and stem cells
Neck - Mucous and parietal cells
Fundus - Chief cells, few parietal cells and enteroendocrine cells
Chief cells
Digestive enzyme secreting cells
Parietal cells
Hydrochloric acid producing cells
Different regions of the stomach
Cardia, body and pylorus
Mucosa of cardia
Deep gastric pits that branch into loosely packed tortuous glands
Mucosa of body
Shallow gastric pits with long straight gastric glands
Mucosa of body
Deep gastric pits with branched, coiled gastric glands
Muscularis externa of the stomach
- Contains an extra layer
- Oblique to the circular and longitudinal layers
- Located internal to circular layer
- Aids in the churning action of the stomach
Gastroduodenal junction
Abrupt transition from stomach mucosa to duodenal mucosa
Duodenum
Contains Brunner’s glands in the submucosa
Jejunum
Tallest villi, located on permanent circular folds of the mucosa and submucosa
What are the circular folds of the small intestine known as
Plicae circularis
Ileum
Characteristic by shorter villi and aggregations of lymphoid follicles
What are the lymphoid follicules of the ileum known as
Peyer’s patches
Enterocytes
Tall columnar cells with a brush border and are the principle absorptive cell
Goblet cells
Produce mucin to protect epithelium and lubricate passage of material
Paneth cells
Found at the base of the crypts of Lieberkuhn, they have a defensive function
Neuroendocrine cells
Produce hormones that contribute to control of secretion and motility
Stem cells
Found at the base of the crypts of Lieberkuhn, the divide to replenish the epithelium
Function of Brunner’s glands
Produce a thin, alkalin mucous to neutralise chyme
Two principle cells of the large intestine
Absorptive cells and goblet cells
Absorptive cells of the large intestine
Removal of slats and water
Goblet cells of the large intestine
Secretion of mucus to lubricate the colon
How are the cells of the large intestine arranged
Straight tubular glands referred to as crypts that extend into the muscualris mucosae
How is the outer longitudinal muscle layer of the large intestine arranged
In 3 muscular strips = teniae coli
Appendix
- Far less abundant crypts
- Circular arrangement of lymphoid tissue
- Lymphoid tissue tends to decline with age
Rectoanal junction
Transition from the mucosa of the rectum to the non-keratinised stratified squamous epithelium of the anal canal
What controls gut motility
The enteric nervous system
What are the plexuses of the enteric nervous system
Myenteric plexus and submucosal plexus
