Alimentary Flashcards
what type of epithelium does the masticatory mucosa have?
keratinised or sometimes parakeratinised stratified squamous epi
what is the term used to characterise nuclei in parakeratinised masticatory mucosa?
nuclei are pyknotic , aka highly condensed.
epithelium of lining mucosa?
non-keratinised stratified squamous
what type of mucosa covers the tounge?
specialised mucosa that contains lingual papillae
which types of lingual papillae contain taste buds?
fungiform, circumvalate, foliate
NOT filiform
what is the origin of enamel?
forms from epithelial cells called ameloblasts
where does dentin. come from
secreted by odontoblasts (columnar epi cells)
origin of salivary glands?
oral cavity epithelium
epithelium of oesophagus?
non-keratinised stratified squamous
what is the pattern of muscularis externa in upper middle and lower levels of oesophagus?
upper is striated, mixed in middle and smooth in lower 1/3.
what epithelium lines the stomach?
simple columnar
how does the lamina propria change in oesophogastric junction?
from loose CT to glandular CT
what are the cavities called in epi of stomach?
gastric pits that go till muscularis mucosa
what are rugae in stomach made out of?
submucosal folds
where are mamillated areas located?
stomach, for increase in SA for secretion
where are prietal cells located, what do they secrete and their nucleus location?
in stomach (neck region and upper parts of gastric pits) and secrete HCL and intrinsic factor (glycoprotein that complexes with VB12, centrally located nucleus
what do chief cells secrete and their nucleus location?
pepsinogen into stomach that converts to pepsin used to break down proteins-basal nucleus
what do enteroendocrine cells produce?
hormones e.g. gastrin
what is special about enteroendocrine cells’ secretions?
their secretions do not go to gastric pits, they go to LP and enter BV, OR act locally.
why are chief cells basophilic basally but eosinophilic in their cyto?
because of lots of rER below nucleus, but lots of zymogen granules in cyto
what are mucous neck cells?
these are STEM cells that give rise to surface mucous cells if they migrate up.
if they migrate down, they differentiate into parietal, chief and enteroendocrine cells.
how can we differentiate different regions in the stomach?
by cell types in glands
and depth of gastric pits.
what is the key gross characteristic of small intestine mucosa?
plicae circulares
what is a lacteal and where are they usually located?
blind-ended lymphatic capillary in the lamina propria of the villus.
where are paneth cells located and what do they produce?
in small intestine (base of glands) which contain refractile secretory granules containing bacterial lysozymes
enterocytes have a ….. located nucleus.
basally
what is the core of a microvillus and what is the significance of it?
actin microfillaments that insert into terminal web. upon contraction of the terminal web the microfilamets allow spread of microvilli to increase SA for absorption
where are lipid droplets in small intestine located?
in vesicles of sER, they migrate out of enterocytes as chylomicrons to lacteals.
features special for duodenum?
brunners glands in submucosa that drain their alkaline secretions into base of crypts of Lieberkuhn
what part of small intestine is the principal site of absorption
jejunum
what is the key feature of ileum?
peyers patches located in lamina propria of villi
what organ does coeliac affect, and what does it cause?
small intestine epithelium, the villus undergoes atrophy and become flat, crypt hyperplasia which causes elongation of them, increase in intraepithelial lymphocytes
what are the key characteristics of large intestine?
no villi/plicae circulares, still have crypts of lieberkuhn, same epithelium cell types except paneth cells, numerous goblet cells, very thick muscularis externa. teniae coli
primary exocrine function of liver?
bile production
endocrine function of liver?
modifies structure and function of hormones e.g. thyroxine
where are portal triads located?
intra-lobularly
how is the flow of blood and bile in the liver classified?
blood is centripetal-towards central vein
bile is centrifugal-from hepatocytes towards portal triad into bile duct
what lines the hepatic sinusoids?
- fenestrated endothelial cells—have a discontinuous basal lamina
- kupffer cells
where does central vein drain into?
sublobular vein which converge to form hepatic vein==>IVC
what is the path of plasma in liver?
plasma left in perisinusoidal space==> periportal space/space of mall
how is bile transported from hepatocytes around liver?
through bile canaliculi which are sealed by zonulae occludens to prevent leakage
function of hepatic stellate cells?
store vitamin A in lipid droplets==> to retina==>forms rhodopsin
Also contributes to ECM remodelling post-trauma
location of stellate cells?
liver perisinusoidal space/disse
what type of cell lines the biliary tree?
cholangiocytes (cuboidal cells)
pathway of bile ?
canaliculi==> intrahepatic ductules aka canals of Hering(lined with cholangiocytes)==>interlobular ducts at portal triad
what controles bile secretion from gall bladder?
hormonal control of enteroendocrine cells cause smooth muscle contraction
what type of epithelium does gallbladder have?
simple columnar with microvilli -no muscularis mucosa and no submucosa
what are Rokitansky-Aschoff sinuses?
formed by mucosa folds when gallbladder is empty- normally prone to inflammation and precursor of gallstones.
describe the appearance of acinar cells of pancreas?
basophilic cyto at base of cell and many zymogen granules in apical part (acidophilia). The acini are composed of simple epithelium serous cells
pathway of acinar cells products in pancreas?
interclated ducts (centroacinar cells)==> adds bicarbonate and water==> intra-lobular (non-striated)==> interlobular (columnar) duct
main type of cells in endo pancreas? and their function?
islets of langerhan
They contain alpha cells: glucagon.
beta cells: insulin
delta cells: somatostatin
