L16: The Enteric Nervous System Flashcards
Which nervous system is the enteric NS part of
Autonomic NS
Is the enteric nervous system part of the intrinsic or extrinsic innervation of the GIT
Intrinsic innervation
What are the 2 plexuses of the enteric nervous system
Myenteric plexus
Submucosal plexus
Which 2 muscle layers is the submucosal plexus found between
Mucosa and circular muscle
Which 2 layers is the myenteric plexus found between
Circular muscle and longitudinal muscle
Which receptors are the afferent sensory neurones associated with
Mechanoreceptors
Chemoreceptors
What does mechanoreceptors detect
Pressure
What does chemoreceptors detect
Chemical
What are the effectors of the enteric NS
Motor
Secretory
What do enteric reflexes do
Motility
Secretion
Blood flow to the gut
Give an example of a motor reflex
Peristalsis
What does the myenteric plexus control
Smooth muscle
Describe the process involved in initiating the myenteric plexus
1) Bolus is detected in the lumen
2) Excitatory pathway is lead from afferent sensory neurones to interneurones and efferents.
3) Git contracts behind the bolus
4) Relaxation in front of the bolus by an inhibitory pathway
What does the submucosal plexus control
Secretory cells
Describe the process involved in the submucosal plexus
1) mechano/chemoreceptors detect distension and chemical
2) submucosal plexus is inactivated
3) this leads to increase in mucous, enzymes and acid
Which plexus is involved in the control of blood flow
Myenteric
Submucosal
Whihc neurotransmitters from the efferent neurone control blood flow
Vasoactive neurotransmitters
What is Chaga’s disease
Parasites get into blood and cause the death of the enteric NS
What is achalasia
An autoimmune disease of the gastro-oesophageal sphincter
What is hirschprung’s disease
Mega colon due to the absence of the ENS
Which main drugs affect the ENS
Opioids
What are the good effects of opioids
Reduce diarrhoea
What is the the bad side effects of opopds
Constipation
