GI Tract: Motility Flashcards
What are the four layers of the GI tract from inside of the lumen to outside (serosa)?
Mucosa
Submucosa
Muscularis Externa
Serosa
What layer of the mucosa is a thin layer of smooth muscle and throws the mucosa into folds and helps mix luminal contents?
Muscularis mucosae
What layer of the mucosa is loose connective tissue which attaches to epithelia and contains blood vessels, lymph nodes and some glands?
Lamina propria
What layer of the GI tract is composed of loose connective tissue, blood and lymphatic vessels, major nerve tracts and some glands?
Submucosa
What layer of the GI tract is made up of INNER circular layer and OUTER longitudinal layer of muscle?
Muscularis externa
What is the outer most layer of the GI tract that is made of connective tissue?
Serosa
What is another name for myenteric plexus?
Auerbach’s plexus
What is another name for submucosal plexus?
Meissner’s Plexu
What is the larger of the two plexuses?
Myenteric plexus or Auerbach’s plexus
What plexus is located between the circular and longitudinal muscle layers (muscularis externa)?
Myenteric plexus or Auerbach’s plexus
What plexus lies in the submucosa of the small and large intestine?
Submucosal plexus or Meissner’s plexus
What plexus is concerned primarily with the control of motility?
Myenteric plexus or Auerbach’s plexus
What plexus is concerned primarily with control of secretion from glands of GI tract?
Submucosal plexus or Meissner’s plexus
Sympathetic innervation is supplied by postganglionics from cells in the ___________ and ___________________ ganglia.
Paravertebral and Prevertebral
What does the sympathetic innervation do to the GI tract?
Inhibits contraction of the muscularis externa &
Stimulates contraction in certain sphincters
The parasympathetic innervation is supplied by _____________ (cholinergic) fibers from the vagus and pelvic nerves.
Preganglionic
How are smooth muscles and glands of the GI tract innervated by parasympathetic innervation?
Preganglionic fibers terminate on ganglion cells in the myenteric and submucosal plexuses, and the axons of the ganglion cells innervate the GI tract.
How does the parasympathetic system act on the GI tract?
Activation increases contraction and secretion
About _____% of vagal fibers and 50% of gut sympathetics are afferent fibers.
75%
Where do the cell bodies of sensory neurons lie?
In the submucosal and myenteric plexuses. The cell bodies of other sensory neurons are located in the DRG and cranial ganglia.
Where do the cell bodies of sensory neurons lie?
In the submucosal and myenteric plexuses. The cell bodies of other sensory neurons are located in the DRG and cranial ganglia.
The cell bodies of the sensory neurons that lie in the submucosal and myenteric plexuses are located in what type of reflex arcs?
Local reflex arcs
The cell bodies of the sensory neurons that lie in the submucosal and myenteric plexuses are located in what type of reflex arcs?
Local reflex arcs
The cell bodies of other sensory neurons are loc
d
The cell bodies of other sensory neurons are located in the DRG and cranial ganglia and these participate in what reflex arc?
Central reflex arcs
What is the membrane potential of GI smooth muscle?
-140 to -80 mV
T/F - Different regions of GI tract have different frequencies.
True
What is the purpose of saliva?
Lubricates food and contains alpha-amylase which begins digestion of starches
Sympathetic activity ________ amplitude of slow waves, where as parasympathetic activity _________ amplitude of slow waves.
Sympathetic activity DECREASES amplitude of slow waves, where as parasympathetic activity INCREASES amplitude of slow waves.
What is mastication?
Chewing
What is the purpose of saliva?
Lubricates food and contains alpha-amylase which begins digestion of starches