Lecture 1- Control of the gut- nerves

Question 1

the GI is under what nervous control

Answer 1

autonomic nervous sytem

enteric nervous system (also hormonal)

Question 2

autonomic nervous system

Answer 2

Parasympathetic and sympathetic

Question 3

Where do the cell bodies of the ANS reside

Answer 3

CNS (brain and spinal cord)

Question 4

pathways of parasympathetic neurones

Answer 4

long preganglionic fibre which synapses with autonomic ganglia outside the CNS

short post ganglionic whcich synapse with peripheral effector organs

Question 5

all preganglionic fibres release

Answer 5

Ach

Question 6

post ganglionic fibres release

Answer 6

Ach, neuropeptides, norepinephrone

Question 7

the parasympathetic nervous sytem is the

Answer 7

on button for the gut (rest and digest)

Question 8

nervous input for the parasympathetic NS which turns the gut on

Answer 8

vagus nerve

pelvic splanchnic nerves (S2-4) (craniosacral outflow)

Question 9

sympathetic NS is the

Answer 9

off button (generally- fight or flight

Question 10

sympathetic innervation to the gut occurs from which levles

Answer 10

T5- L2

Question 11

sympathetic nerves

Answer 11

pass through (paravertebral) sympathetic trunk without synapsing

Question 12

sympathetic nerves pass through (paravertebral) sympathetic trunk without synapsing forming

Answer 12

o Greater(T5-9)
o Lesser(T10-11) o Least(T12)

Question 13

splanchin nerve synapse with

Answer 13

􏰀 These splanchnic nerves synapse with prevertebral ganglia

Question 14

sympathetic nerve mainly innervate

Answer 14

blood vessels

Question 15

summary of parasympathetic NS and the GI

Answer 15

􏰀 Originates in brain and sacral spine (craniosacral)
􏰀 Vagus- oesophagus-transverse colon
􏰀 Pelvic nerve- transverse colon-anal canal
􏰀 Long preganglionic fibres extend to viscera (postganglionic fibres essentially in visceral wall)
􏰀 to myenteric and submucosal plexuses (enteric ns)
􏰀 Releases Ach or a neuropeptide like GRP
􏰀 Switches on gut functions

Question 16

summary of sympathetic NS and the GI

Answer 16

􏰀 Originates T1-L2 spine
􏰀 Preganglionic fibres (pathway)
o Spinetosympatheticchain,passthroughchain
without synapsing, join with other preganglionic fibres to form splanchnic nerves (greater, lesser, least), splanchnic nerves synapse on prevertebral ganglia (coeliac, superior mesenteric and inferior mesenteric)
􏰀 Postganglionic fibres extend from prevertebral ganglia to viscera
o tomyentericandsubmucosalplexuses(entericns)
􏰀 Generally inhibits function

Question 17

the enteric nervous system

Answer 17

􏰀 One of the divisions of the nervous system
􏰀 Can operate completely independently (second brain)
􏰀 But has extensive connection with the ANS 􏰀 100’s of millions of neurones
􏰀 Exists from oesophagus to anus

Question 18

two main plexus’ of the ENS

Answer 18

􏰀 Submucosal (Meissner’s)
–> Submucosa
􏰀Myenteric (Auerbach’s)
–> In between circular and longitudinal muscle

Question 19

submucosal (Meissner) plexus responsible for

Answer 19

􏰀 Secretions

􏰀 Blood flow

Question 20

myenteric (Auerbachs) plexus responsible for

Answer 20

motility

Question 21

the ENS communicates with:

Answer 21

Communicates with:
􏰀 Parasympathetic (vagus and pelvic nerves)
􏰀 Sympathetic (prevertebral ganglia)