| Question | Answer |
| GRP | Grastrin Releasing Peptide
Releases Gastrin |
| Action of Gastrin | Stimulates gastric acid secretion
Growth of gastric oxyntic gland mucosa |
| Gastrin site of release | Antrum (duodenum) |
| Releaser of Gastrin | Amino Acids
Distention
Vagal Stimulation |
| CCK | Cholecystokinin |
| CCK stimulates | Gallbladder contraction
Pancreatic enzyme secretion
Pancreatic bicarb secretion
Growth of exocrine pancreas
Pepsin secretino |
| CCK inhibits | Gastric emptying |
| CCK site of release | duodenum and jejunum |
| What releases CCK? | Peptides
Amino Acids
Fatty acids > 8carbons |
| Secretin stimulates? | pancreatic bicarbonate secretion
biliary bicarbonate secretion
Growth of exocrine pancreas
Pepsin secretion |
| Secretin inhibits? | Gastric acid secretion
Trophic effect of gastrin |
| Secretin is released ? | duodenum |
| What causes release of secretin? | acid (fat) |
| What does GIP stimulate? | Insulin release |
| What does GIP inhibit? | gastric acid secretion |
| What does GIP stand for? | Gluco-dependant Inuslotropic Peptide
Gastric Inhibitory Peptide |
| Motilin stimulates? | Gastric motility
Intestinal motility |
| Motilin is released at | duodenum and jejunum |
| What causes release of motilin | nerves (fat and acid) |
| What are neurocrins? | located in nerves and released into the blood to affect distant target tissue |
| What are the 4 neurocrines? | VIP
GRP
enkephalins
neurotensin |
| VIP | vasoinhibitory peptide
both stimulatory and inhibitory secretion
Inhibits gastric secretion
causes relaxation of GI smooth muscle |
| GRP | Gastrin-releasing peptide |
| What nerves release GRP? | Vagus |
| What is GRP's action? | Gastrin release |
| Enkephalins | opiates
decrease motility and decrease intestinal secretion |
| What common disorder are enkephalins good for? | diarrhea |
| Neurotensin | increases blood glucose by stimulating glycogenolysis and glucagon release
INHIBITS insulin release |
| Paracrines | somatostatin
histamine |
| Somatostatin | Inhibits everything |
| Histamines | Induce parietal cells
comes from ganglia |
| Candidate Hormones | Pancreatic polypeptide
Peptide YY
Enteroglucagon |
| Pancreatic polypeptide | Decreases pancreatic bicarb and enzyme secretion.
Released by protein, fat and glucose |
| Peptide YY | Inhibits gastric secretion and emptying
Released by fat |
| Enteroglucagon | Inhibits gastric secretion and emptying
Stimulates insulin release
Released by Hexose and Fat |
| How are the distal rectum and anal canal innervated | sympathetic fibers from the hypogastric plexus |
| Parasympathtic nerves _____________ the GI. | stimulate |
| Sympathetic nerves _____________ the GI. | inhibit |
| SNS ____________ sphincters | contracts |
| SNS _________ tone/motility of the GI. | decreases |
| PNS _________ sphincters. | relaxes |
| PNS ______________ of smooth muscle of the GI. | increases motility |
| Can the enteric nervous system function independently? | yes |
| What modulates enteric output? | extrinsic nervous system |
| Enteric nervous system | Subdivision of peripheral nervous system that directly controls the GI system. |
| Extrinsic nervous system | Everything outside the enteric nervous system |
| Parasympathetic pre-ganglion synapse onto _________ | enteric ganglion |
| Post-ganglionic nerves from the enteric nervous system synapse __________. | on target cells and other enteric nerves. |
| Anything leaving the enteric nervous system is ______________. | post-ganglionic |
| 3 types of post-ganglionic nerves leaving the enteric system. | post-ganglionic parasympathetic
post-post-ganglionic sympathetic
post-enteric |
| What are the two main plexus found in the GI | myenteric and submucosal |
| Where is myenteric plexus located? | just under the longitudinal muscle |
| Where is the submucosal plexus found? | Just under the circular muscle |
| Myentery plexus innervates ____________. | Outer muscles |
| Submucosal plexus innervates _____________. | Crypts and villi. |
| What kind of information is carried on the vagus nerve? | afferent and efferent |
| The classic exitatory neurotransmitters are | ACH and Substance P |
| The classic inhibitory neurotransmitters are | VIP and NO |
| VIP is located exclusively within | nerves |
| Two reflexes in the GI | Vasovagal Reflex
local/intramural reflexes |
| Vasovagal reflex | afferent information goes from gut to CNS then efferents return to the GI to correct the situation |
| Local reflexes and intramural reflexes occur | only in the gut wall |
| Hormonal control of teh GI tract | cell-cell
autorcine
paracrine
nervous
endocrine
neuroendocrine |
| Cell-cell control | thru gap junctions |
| autocrine control | cell secretes a hormone that regulates itself |
| paracrine | target cell is near signaling cell |
| Nervous control of the GI | neuron releases thru a synapse to target cell |
| Endocrine control | endocrine cell releases hormone to blood stream then goes to target cell |
| Neuroendocrine control | Nerve releases hormone to bloodstream then goes to target cell |
| Distension inhibits | gastrin |
| Protein stimulates | Gastrin
CCK
GIP |
| Fat stimulates | CCK GIP |
| Acids/Fatty Acids stimulate | Secretin |
| Acids/fatty acids inhibit | Gastrin |
| Glucose stimulates | GIP |
| Motilin is released | cyclically every 90 minutes during fasting |
| What inhibits motilin? | mixed meal |
| ECF | enterochromaffin-like cells
release histamine |
| Zollinger Ellison | Gastrin secreting tumors in the pancreas |
