Enteric Nervous System NOT FINISHED

Question 1

The enteric nervous system is known as the intrinsic innervation of the GI tract. What is meant by intrinsic?

Answer 1

All neural elements are within the GI tract

Question 2

What are the 2 major plexuses of ganglion cells? What do they supply?

Answer 2

Submucosal plexus - stomach and intestines only

Myenteric plexus - full length of GIT

Question 3

Where are the 2 plexuses located?

Answer 3

Submucosal - Above the submucosa and below the circular muscle
Myenteric - Above circular muscle and below longitudinal muscle

Question 4

Give 2 examples of sensory receptors within the GI tract?

Answer 4

mechanoreceptors

chemoreceptors

Question 5

Give 2 examples of effectors within the GI tract?

Answer 5

smooth muscle

glands

Question 6

What is the submucosal plexus responsible for?

What is the myenteric plexus responsible for?

Answer 6

secretory reflex

peristalsis

Question 7

The neurotransmitter can have different effects at each effector. What are these?

Answer 7

inhibitory @ smooth muscle

excitatory @ secretory glands

Question 8

What are the excitatory and inhibitory NT’s at motor effectors

Answer 8

inhibitory = NO, VIP, ATP
excitatory = ACh, substance P, 5-HT

Question 9

What does VIP stand for?

Answer 9

vasoactive intestinal peptide

Question 10

What enables the same neurotransmitter to have different effects?

Answer 10

different receptors

Question 11

What are 4 diseases associated with the enteric nervous system?

Answer 11

Hirsprung’s disease - congenital absence of ENS neurones
Chaga’s disease - tryoanosome parasite –> neuronal death, stops peristalsis
IBS - dysfunctional interaction between CNS and ENS
General neurological conditions e.g. Parkinson’s, MG