click below
click below
Normal Size Small Size show me how
WVSOM -- Physio
WVSOM -- Neural and Hormonal control of the GI system
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 |