1.08 Gut Function + Innervation Flashcards
(50 cards)
What plexus is responsible for control of secretory functions, absorption, and blood flow?
Submucosal plexus
What plexus is responsible for control of motility regulating circular and longitudinal muscle?
Myenteric plexus
What is the origin of parasympathetics in GI tract?
Medulla oblongata = CNX
Sacral spinal cord = pelvic splanchnic nerves
What is the role of parasympathetics in GI?
Increase motility, secretions, blood flow, and relaxation of sphincters
What organs do the cranial division of the parasympathetics innervate?
Esophagus, stomach, small intestine, large intestine (cecum, ascending, and proximal 2/3 transverse)
What kind of receptors are the postganglinic neurons terminateing on smooth muscle or glans within the parasympathetic system?
Muscarinic
What neurotransmitter is used for the parasympathetics?
Ach
What kind of receptor is present when Ach is released from the preganglionic vagus nerve to the submucosal or myenteric plexus?
Nicotinic
What organs are innervated by the parasympathetic sacral division?
1/3 transverse colon, descending, sigmoid, rectum, anal canal to sphincter
What sacral levels do the parasympathetic pelvic splanchnic nerve arises?
S2-S4
Where do the postganglionic neurons of PARA originate?
Terminal ganglia of myenteric/submucosal plexus
What are the neuron structure/trends of the PARA pre and post ganglionic neurons?
Pre = long, myelinated , fast
Post = short, unmyelinated, slow
What is the difference between nicotinic and muscarinic receptors?
Nicotinic = ligand gated ion channels
Muscarinic = GPCR
What spinal levels do the sympathetic nerves originate from?
T5-L2 (thoracolumbar nerves)
What is the sympathetic innervation relationship to sphincter muscle?
Inhibitor to non-sphincter
Excitatory to sphincter (contract)
What are the sympathetic roles to digestion?
Decrease motility, secretions, blood flow (vasoconstrict) and contract sphincters
What are the neuron structure of pre and post ganglionic neurons in the sympathetic system?
Pre = short, myelinated, fast
Post = long, unmyelinated, slow
What neurotransmitters do the pre and post ganglionic neurons release in SYM?
Pre = Ach
Post = NE
What are the sympathetic prevertebral ganglia?
Celiac, superior mesenteric, inferior mesenteric
The release of NE from postganglionic SYM neuron to what receptor allows for smooth muscle relaxation?
B2
The release of NE from postganglionic SYM neuron to what receptor allows for sphincter contraction?
A1
The release of NE from postganglionic SYM neuron to what receptor allows for secretion suppression?
A2
The release of NE from postganglionic SYM neuron to what receptor allows for vessel vasoconstriction?
A1
What kind of neurons are confined to the enteric nervous system as a single axon with multiple branches to detect mechanical, chemical, and thermal changes?
IPANs (intrinsic primary afferent neurons)
