Anatomical and Neural factors Flashcards
Name the 7 spincters of the GI tract
UES LES Pyloric Sphincter of Oddi Ileocecal Internal anal External Anal
Dense nerve network in the submucosa.
Best developed in the small intestine.
Controls gastrointestinal secretion
Meissner’s Plexus (Submosal plexus)
Nerve network located between the inner circular layer and outer longitudinal layer of muscularis externa
Well developed through the entire length of the gut
controls gastrointetsinal movment
Auerbach’s Plexus (Myenteric Plexus)
neurotransmitter used by interneurons in the intramural plexus (local reflexes)
Serotonin (5HT)
Why do we need ANS in the gut? Is Enteric enough
required for coordination of GI movements
Enteric can provide most of the functional characteristics on its own
Law of the gut
muscle activation (contraction) on the oral side of the bolus and muscle relaxation on the caudal side of the bolus
Neurotransmitters that cause excitation (contraction)
ACh, Substance P
Neurotransmitters that are inhibitory (relaxation)
VIP, NO
Preganglionic parasympathetic fivers
Mostly cholergic and exitatory. Terminate in the ganglia of neural plexuses. share their post ganglionic fibers with the ENS
** Postganglionic neurons are part of ENS
Sympathetic fibers
Generally adrenergic inhobitory for paravertebral ganglia
How does sympathetic innervation decrease motility and secretion
NE released inhibits parasympathetic ACh release by activating alpha-2 presynaptic receptor
Reduced motility and secretion
Innervation of blood vessels of the gut (through what receptor)
Sympathetic fibers through alpha 1 cause vasoconstriction - causes reduced secretion
Resting membrane potential of the gut
-40 to -80
What controls basic Electrical Rhythm (BER)
Pacemaker cells (cells or Cajal)
BER Frequency of the stomach
3/min
