Gastrointestinal Flashcards
general hollow organ organization
mucosa, submucosa, muscularis externa
elements of mucosa
epithelial lining, lamina propria (CT), muscularis mucosa (SM)
Muscularis externa
This can have two layers: inner circular and outer longitudinal
Esophagus layers
mucosa, submucosa, muscularis externa, outer CT (adventitia and serosa
esophagus specializations
plexi, glands, GE junction
esophagus plexi
nerve and submucosal
esophagus glands
submucosal, mixed seromucus. Duct is stratified cuboidal
Esophagus GE junction
rapid transition of epithelia type. Metaplastic changes occur with chronic GERD
Stomach sections
cardia, fundus, parietal. Simple columnar epithelia.
Cardia
region of stomach that meets esophagus, closest to heart. Contains short glands/pits. Cells are mucus and EE
Fundus
body of stomach, contains long rug and short pits with Long glands. Cels are parietal, chief, and mucus.
Periatal cells
look like fried eggs, intracellular caniculi with lots of mitochondria
chief cells
basophilic, protein secreting. Pepsinogen is secreted, which becomes pepsin at acidic PH
Pyloric region
contains long pits, short clans. Mucous and EE cells. The sphincter is thickened inner muscular external region.
Enteroendocrine cells
abundant in stomach. secrete lots of products. Require a special stain to see these.
Small intestine GE junction
epithelia change from no microvilli to microvilli
small intestine components
duodenum, Jejunum, Ileum
General small intestine characteristics
villi, many goblet cells, crypts (will many cell types)
Crypts
invaginations into Lamina propria, appear like flowers with central lumen.
Cells in crypts
goblet cells, paneth cells, EE (open and closed)
goblet cells
unicellular with no microvilli. Number increases distally down the intestine
Paneth cells
at the base of crypt. Antimicrobial eosinophilic granules.
EE open vs closed (in crypts of SI)
open: surface is exposed to lumen. Both have granules at the basal end.
Villi specializations
SM, epithelia, and lymphatic capillaries
SM in villi
located in lamina propria, help contract lymph
Epithelia in Villi
microvilli, terminal bars. Simple columnar. Also contain glycoxalyx, which concentrate enzymes.
Lympathics in Villi
absorb lipids, shuttle to laima propria
Duodenum characteristics
villiform, Brunner glands
Brunner glands
submucosal glands that neutralize chyme with alkaline secretions
Jejunum
contains place circulates and teniae coli, NO GLANDS
plicae circulares
infoldings of submucosa
Ileum
can have some place. Contains lymphocytes and peyers patch (with M cells)
Colon
no villi, crypts, lots of goblet, EE
Appendix
lymphocytes, no villi, crypts
Liver functions
metabolic, exocrine, endocrine
Liver structure
highly cellular, CT capsule, hexagonal lobules, which contain central vein and dual blood supply
sinusoids of liver
discontinuous epithelium, reticular fibers, overlie Disse region, blood flow
Cells in liver
hepatocytes, kuffer, Ito
Bile caniculi
located in between hepatocytes, move bile towards duct
Kuffer cells
macrophages that can move freely on the lumen side
Ito cells
store vitamin A, activated by damage
Portal tract components
Portal vein, hepatic artery, bile duct, lymphatics (sometimes)
Liver lobule types
classic, portal accinus
central vein, triangle from ducts, between central veins (oval)
Gall Bladder
bile storage/concentration, no MM/submucosa, no goblet, contains false glands
false glands
continuous with lumen, located in gallbladder
Hormones that act on gallbladder/pancreas
CCK-contraction
Secretin-Bicarbonate secretion
Epithelium of gallbladder
simple columnar. They concentrate bile by creating osmotic gradient and absorbing h2o
Pancreas exocrine function
highly lobulated with septa, contains serous acini which contain zymogen granules. Has inter and intralobular ducts
