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39 Cards in this Set
- Front
- Back
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What type of neurons are used for the integration of sensory input with motor output in the ENS?
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Interneurons
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What stimulates the secretion of salivary glands, stomach, and pancreas?
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Acetylcholine
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What inhibits contractions of smooth muscle and stimulates secretion of the pancreas and intestines?
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Vasoactive Intestinal Peptide (VIP)
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What stimulates secretion of the GI hormone GASTRIN?
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Gastrin Releasing Peptide (GRP)
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What stimulates smooth muscle contraction (NOT PERISTALSIS) and inhibit intestinal secretion
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Enkephalins
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Inhibits intestinal secretion of water and electrolytes and inhibits smooth muscle contraction.
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Neuropeptide Y
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REMEMBER
SUBSTANCE P = CONTRACTION OF SMOOTH MUSCLE |
REMEMBER
SUBSTANCE P = CONTRACTION OF SMOOTH MUSCLE |
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? modulates the release of ACh, gastrin, somatostatin, serotonin, histamine, and prostaglandins.
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GABA
Gamma-amino butyric Acid |
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Describe what Gastrin does
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Stimulates gastric motility
INHIBITS gastric emptying stimulates secretion of HCl Stimulates growth of gastric mucosa |
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Describe what Cholecystokinin (CCK)
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Inhibits gastric emptying
stimulates contractions of gallbladder stimulates pancreatic enzyme secretion stimulates growth of exocrine pancreas potentiates the effects of secretin |
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What type of cells secrete Cholecystokinin (CCK)
What stimulates it? |
I cells of Duodenum
fatty acids amino acids peptides |
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What type of cells secrete Secretin?
What stimulates it? |
S cells of Duodenum
pH < 4.5 |
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Describe what Gastric Inhibitory Peptide (GIP) purpose
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stimulates secretion of INSULIN
INHIBITS gastric emptying and secretion of HCl |
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What secretes Gastric Inhibitory Peptide (GIP)?
What stimulates it? |
Duodenum and Jejunum
Fatty acids amino acids glucose |
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What stimulates Gastrin production?
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vagal stimulation
amino acids gastric distention small peptides |
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What secretes Motilin?
What stimulates it? |
Duodenum and Jejunum
Fasting |
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What does Motilin do?
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Interdigestive migrating motor complex
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What does CCK-A receptors require a ? at position 7 of the C-terminus.
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Sulfated Tyrosine
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What do CCK-B receptors require for binding?
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amidated C-terminus
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Interstitial cells of Cajal (ICC) are primarily confined what plexus?
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Myenteric Plexus
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True or False
CCK and Gastrin can bind to related receptors CCK-A and CCK-B |
True
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Sympathetic innervation of the ENS is mainly via ? fibers whose cell bodies are located in prevertebra and peri-vertebral ganglia.
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POSTGANGLIONIC NERVE FIBERS
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What is the Vago-Vagal reflex?
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mediated normal gastrointestinal activity
most vagal fibers are SENSORY |
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Make sure to go over FIG. 2-4 and 2-5
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Make sure to go over FIG. 2-4 and 2-5
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What stimulates Vago-Vagal reflex pathway?
What are the effects? |
Gastric Distention
-Receptive relaxation of proximal stomach -stimulation of gastric secretion HCl and Gastrin -regulation gastric motility |
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What stimulates the Gastroileal reflex pathway?
What are the effects? |
Gastric Distention
-Stimulates motility of ileum -relaxation of ileocecal sphincter |
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What stimulates the Gastrocolic reflex pathway?
What are the effects? |
Gastric Distention
-Stimulates motility of colon |
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What stimulates the Enterogastric reflex pathway?
What are the effects? |
Acid, fat and protein in duodenum
-Inhibits gastric gastric emptying |
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What stimulates the Ileogastric reflex pathway?
What are the effects? |
Distention of ileum
-inhibits gastric emptying |
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What stimulates Intestino-intestinal reflex pathway?
What are the effects? |
Distention in a part of the intestine
-Inhibits motility below the site of distention |
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Visceral Smooth Muscle has neural contact through ?
Communication among muscle cells via ? |
Varicosities
gap junctions (electrical syncytium) |
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True or False
In visceral smooth muscle -- Action Potentials synchronized with SLOW WAVES produce contractions. |
True
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Describe the sequence of events of smooth muscle contraction?
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Ach binds to muscarinic receptors
Myoplasmic [Ca2+] increases Ca2+ binds to CALMODULIN Calmodulin-dependent MLCK activated Myosin phosphorylated Myosin ATPase activity increases and cross-bridges form between myosin and actin Contraction occurs Dephosphorylation of myosin by MLCK Relaxation (phasic) or Latch (tonic) |
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What initiates a visceral smooth muscle action potential?
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extracellular Ca2+ enters through VOLATE-ACTIVATED and RECEPTOR-ACTIVATED Ca2+ channels
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Failure of the Na+/K+ pump will have what affect on Ca2+ in visceral smooth muscle?
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3 Na+ (in) / 1 Ca2+ (out) anti-porter pump failure
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When Visceral Smooth Muscle has depletion of Ca2+ stores in SR this leads to ?
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Activation of STORE-OPERATED Ca2+ Channels (SOCs)
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True or False
Ca2+ entry through SOCs and release of Ca2+ from the SR is VOLTAGE-INDEPENDENT |
True
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Stimulation of Sarcolemma receptors activate ? which generates ?
=> then causes ? to occur. |
activate PLC
generates IP3 stimulates opening of Ca2+ channels in SR |
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Describe Phasic Contractions
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myoplasmic [Ca2+], Cross Bridge Phosphorylation and FORCE reach a peak and then return to baseline.
ICC generate slow waves that cause hypo-polarize smooth muscle Phasic contractions are synchronized with GI slow waves Action potentials on the crests of slow waves cause contractions and increased tension int he contracting muscle |
