digestive system small intestine Flashcards
how does the Si produce intestinal hormones?
using DNES cells
what 3 surface adaptations increase surface area of Si?
plicae circulares
villi
microvilli
what is another name for plicae circulares?
valves of Kerckring
what are the permanent folds affecting the mucosa and submucosa found throughout the duodenum, jejunum and proximal ileum?
plicae circulares
where are the microvilli of the small intestine located?
on the luminal cell surface
what is the surface epithelium of the small intestine (Si)
simple columnar
what are the 6 cell types of the Si?
surface absorptive cells- enterocytes goblet cells DNES cells regenerative cells paneth cells M (microfold) cells
which cell type absorbs water and nutrients and has terminal digestion in the glycocalyx?
surface absorptive/ enterocytes
where are goblet cells of Si concentrated?
fewest in duodenum and most in ileum
how many types of DNES cells do we have in the Si?
11 types
which type of DNES cell stimulates CCK?
type I
what hormone stimulates gallbladder contraction and pancreatic secretion of enzymes from serous acini?
CCK
which type of DNES cell produces GIP and inhibits HCL release?
type K
which DNES type produces secretin?
type S
what hormone stimulates pancreatic secretion of bicarbonate from the pancreatic ducts and also inhibits HCL release and movement of chyme into Si?
secretin
where are regenerative cells found and how long do they live?
found in crypts and live 5-7 days
how long do paneth cells live?
20 days
where are paneth cells located?
base of the crypts (intestinal glands)
what is the fx of the paneth cells?
produce lysozyme
what cells are located at the ileum epithelium over Peyer’s patches?
M (microfold) cells
what cells contain large intracellular pockets that are fairly open to the lamina propria?
M (microfold) cells
what is the function of the M cells?
promote humoral immunity
- causes plasma cells to produce IgA which is then transferred to epithelial cells and released into gut lumen
- important for maintaining gut flora
what is the lamina propria of the Si made of?
loose areolar CT
if the longitudinal muscle of villus core is irritated then the muscle contracts and the villi shorten. What can this lead to long term?
nutrient deficiencies
