Overview GI Lecture 15 Flashcards
Example of intrinsic and extrinsic signalling mechanisms working together
Vago-vagal reflex, afferent up vagus nerve, efferent down vagus to intrinsic signalling system
Locations of sympathetic signalling hubs
Celiac, sup. mesenteric and inf. mesenteric ganglia
List hormonal peptides to know for GI
CCK, gastrin, secretin, motilin, GIP
Gastrin, source, target, mechanism, action
Source- G cells of antrum Targets - parietal cells; ECL cells Mech. - endocrine Action - parietal - incr. H secretion ECL cells - incr. histamine
CCK, source, target, mechanism, action
Source - I cells in small intestine Targets - pancreatic acinar cells; gallbladder smooth muscle Mech. - endocrine Action - acinar cells - incr. secretion muscle - contraction
Secretin, source, target, mechanism, action
Source - S cells in small intestine
Targets - pancreatic ductile cells; multiple cell types in stomach
Mechanism - endocrine
Action - ductile cells - incr. H2O and bicarb. secretion;
stomach cells - decrease H secretion
Somatostatin, source, target, mechanism, action
Source - D cells of stomach
Targets - Parietal, ECL cells and G cells
Mech. - paracrine
Action - decreased H, histamine and gastrin secretion
Motilin, source, target, mechanism, action
Source - endocrine cells in stomach and duodenum
Targets - smooth muscle in those areas
Mech - endocrine
Action - incr. contraction
Gastrin releasing peptide (GRP) - source, target, mech. action
Source - enteric neurons in antrum/pancreas
Target - G cells; duct cells
Mech. - neurocrine
Action - incr. gastrin/incr. H20 and bicarb
VIP - source, target, mechanism, action
Source - enteric neurons
Targets - pancreas acinar cells; LES smooth muscle; intestinal epithelium
Mech. - neurocrine
Action - incr. enzyme secretion; relaxation; incr. H2O secretion
Movement through tight junctions is called…
and is dependent on the gradients in the…
paracellular - lumenal and serosal sides
Four processes of food motility
propulsion, separation, storage, mixing/mechanical disruption
slow waves in GI smooth muscle are…
the basic electrical rhythm of the cells and carry the cells closer to AP’s
pacemaker cells in the intestine are called…
and use what two types of channels?
Interstitial Cells of Cajal
DHP-insensitive Ca channels and Ca sensitive IRK channels
Resting state for GI tract is called?
is altered by?
ileus
inhibiting the inhibitors thereby causing contraction of smooth muscles
