Flashcards in Phys Johnson GI regulation Deck (33):
4 major functions of the GI tract
SNS and PNS in GI tract. location of layers, who synapses there. 2 in wall, 2 outside for each.
Myenteric plexus, SNS & PNS
Submucosal plexus, SNS & PNS
vagus & pelvic nerves, PNS
sympathetic ganglia, SNS
largest component of PNS runs in what structure?
Amount of PNS in vagus effarent vs affarent
those that have affarent and efferent
how endocrine hormones travel wrt GI
in the blood, not lumen
4 qualifications to call something a true hormone
1 secretion from a response
2 absence of innervation dependance
gastrin structure, 2 types
is sulfation important?
G34, G15 are big & little.
4 AAs at C-terminus are action site.
produced in G-cells in the stomach
6 AAs identical to gastrin
always sulfated for CCK effect
I-cells of duod & jejunum
difference in structure of gastrin and CCK
tyrosine in 6th (gastrin) or 7th (CCK) position from c-terminus
whether it's sulfated
secretin structure & importance of that structure
entire sequence is essential, no active fragments
location of gastrin secretion
antrum, some duodenum
location of CCK secretion
duodenum, jejunum, some ileum
location of secretin secretion
duodenum (requires acidic pH, so looses effect distally)
location of GIP secretion
duodenum & jejunum
location of motilin secretion
duodenum & jejunum
Gastrin released by?
protein, distention, nerves
CCK released by?
secretin released by?
GIP released by?
protein, fat, carbs
motilin released by?
actions of gastrin
increase acid, mucosal growth
bicarb increase, pancreatic enzyme secretion, gallbladder contraction, reduced gastric emptying, pancreatic growth
increased bicarbonate (major, pancreated & bile)
intestinal & gastric motility
relaxes gut and sphincters via NO production
stimulates gastrin release
stim sm muscle contraction
inhibits intestinal secretion
(opposite of VIP)
Somatostatin actions in stomach
inhibits gastrin & hormone peptide release
released by acid
inhibited by vagus
Histamine actions in stomach
overproduction of gastrin
ulcers, diarrhea, steatorrhea, high acid, inactivation of pancreatic lipase