SI Phys and Path again Flashcards
What are the 3 regions of the small intestine
Duodenum
Jejunum
Ileum
which region is the shortest and widest portion of the small intestine
duodenum
which region starts at the pyloric sphincter?
duodenum
which region is C-shaped and mostly retroperitoneal?
duodenum
which region is closely associated with the head of the pancreas?
duodenum
which region of the small intestine is the longest?
ileum (2 meters)
which region joins the large intestine at ileocecal sphincter?
ileum
the vast majority of the duodenum is ?
retroperitoneal
jejunum has what?
larger plicae circulares
the ileum has many ?
large lymphoid nodules (peyer’s patches)
the arterial supply for the first 2/3 of the duodenum comes from?
the hepatic artery of the celiac trunk
- Hepatic art. -> gastroduodenal art. -> superior pancreaticoduodenal art.
the arterial supply for the rest of the small intestine (last part of duodenum to ileum) comes from
the superior mesenteric artery
what receives venous blood from small intestine and portions of the large intestine, stomach, and pancreas
superior mesenteric vein
what are plica circulares?
folds of mucosa and submucosa, they are permanent ridges about 10 mm “tall”
what encourages mixing and cause chyme to spiral and slosh through the intestine
plica circulares
what are finger-like projections of mucosa that are 0.5-1 mm long and vastly increase the SA of epithelium
villi
what is too small to be seen individually and is called?
microvilli and brush border
what does L cells secrete?
Peptide YY
what does Peptide YY do?
inhibits gastric secretion and motility = slows gastric emptying
how is chyme propelled through the small intestine
peristaltic waves (peristalsis)
what is a peristaltic rush
a powerful wave of contractile activity that travels long distances down the small intestine
what causes a peristaltic rush
intense irritation or unusual distension
what is the “law of the gut”
distention in the alimentary canal causes distal parts of the canal to relax and proximal parts to contract
peristalsis is enhanced by?
- gastrin
- CCK
- serotonin
peristalsis is inhibited by?
- secretin
- peptide YY
- epinephrine
what are the requirements for gastric emptying into the small intestine (duodenum)
- food particles must by very small
- small volumes of low pH fluid
- gradual release
what is the major organ that regulates the rate of gastric emptying
duodenum
what are some duodenal hormones?
CCK and Secretin
what substances release the most CCK
fats
what is the major paracrine regulator of gastric emptying
CCK
- increased CCK release = slowed gastric emptying