GI - histology Flashcards
what kind of epithelium is found in oral cavity, oropharynx and larygopharynx
stratified squamous epithelium
describe the epithelium on the dorsal/ventral surfaces of the tongue
anterior 2/3 ventral - thin dorsal - thick with papilla posterior 1/3 dorsal - smooth stratified squamous epithelium which lacks papillae except circumvallate but has substantial lymphoid aggregates in submucosa
describe the epithelium of the nasal cavity and nasopharynx
ciliated pseudostratified columnar epithelium with goblet cells (respiratory)
what are the 4 papilla found in tongue and which isn’t used for taste
fungiform
circumvallate
filiform - not taste
foliate
where are submucosal glands found
submucosa of oesophageal lining and duodenum
what is the Z line and what gives it its appearance
gastro-oesophageal junction
stratified squamous epithelium to columnar epithelium
where are gastric pits found and what do they contain
found in mucosa of stomach cells, lined by surface mucous cells which contain gastric glands - parietal cells and chief cells
what do parietal cells secrete
intrinsic factor and HCL
what do chief cells secrete
pepsinogen
where in the stomach does the smooth muscle thickness of the muscularis external increase
pyloric sphincter
what are villi
finger like projections found on mucosa of small intestine surfaces
what are crypts of lieberkuhn
pits found next to villi on small intestinal mucosa and in large intestine
what kind of cells are enterocytes
main absorptive cells of small intestine
tall columnar cells with brush border
what kind of cells are goblet cells
small intestinal glands that produce mucin which protects and lubricates cells and moves things along
what is the function of paneth cells
antibacterial function
what is the function of enteroendocrine cells
produce hormones to control gastrin secretion and motility
CCK, VIP, Gastrin
where are stem cells found in the gut
bottom of crypts of lieberkuhn
what are brunners glands
found in duodenum
release alkaline mucous to neutralise HCL in chyme
where are the tallest villi found in small intestine
jejeunum
what are the 4 main layers of the GI tract
mucosa
submucosa
muscularis externa
serosa/adventitia
what is the mucosa made up of
epithelium (sits on basal lamina) - absorption
exocrine cells
endocrine gland cells
lamina propria (loose connective tissue) - capillaries, enteric neurones and immune cells
muscularis mucosa (thin layer of SM) - contraction causes changes in absorptive and secretory area of mucosa - facilitates absorption
what makes up the submucosa
loose connective tissue
larger blood and lymph vessels
what makes up the muscularis externa
circular (inner) and longitudinal muscle (outer)
myenteric plexus
what are the 3 layers of longitudinal muscle called in the large intestine
teniae coli
what is the serosa/adventitia
outer layer of connective tissue that either suspends digestive tract or attaches it to other organs
true/false
the appendix has a lot of lymphoid tissue
true
what are the 2 nerve plexuses of the enteric nervous system and where are they found
submucosal plexus (in submucosa) myenteric plexus (between circular and longitudinal muscle of muscularis externa)
what do oxyntic cells look like
pink fried eggs with purple yolks
what is a Schatzki’s ring
beginning of a stricture
how do the myenteric and submucosal plexuses connect
interganglionic fibre tracts
