Physiology Flashcards
upper GI function
intake source and receptacle
initial digestion occurs
middle GI function
site where most of digestion and absorption occurs
lower GI tract function
storage channel for elimination of waste
4 layers of of GI wall +fxn
inner mucosal
submucosal (support)
muscularis (peristalsis, circular layer, longitudinal layer)
outer serosa
types of muscle contractions
mass movements tonic contractile phasic contractile segementing haustral
peristalsis contractile activity
serves to propel forward food
mass movements
propulsive movement of unit within large intestine
tonic contractile activity
found between two organs, stable contraction
occludes lumen
typically in LES, UES, other sphincter
phasic contractile activity
periodic contraction
lasts few seconds and followed by relaxation
segmenting contractions
mix chyme with secretions and bring contents into contact with mucosa for digestion and absorption
haustral contractions
segmenting contraction with longer duration
components of enteric nervous system
myenteric plexus
submucosal plexus
myenteric plexus
aka Auerbach
between circular and longitudinal calls
concerned with motility
submucosal plexus
AKA Meissner
controlling function of ea. segment of intestinal tract
SNS effect on GI tract
via thoracocolumbar spinal cord
stimulation cause decrease in activity + decreased motility and secretions
PNS effect on GI tract
via vagus nerve
cause increase in activity including increased motility and secretions
areas of striated muscle in GI
pharynx, upper third of esophagus, external anal sphincter
increased smooth muscle ocontraciotn when
PNS stimulation
stretching smooth muscle (gas or constipation)