Little Brain

Question 1

parasympathetic nervous system

Answer 1

cranio sacral outflow
has depressor effects

Question 2

sympathetic nervous system

Answer 2

thoraco-lumbar outflow
pressor effects

Question 3

enteric nervous system

Answer 3

distinct from PNS and SNS
>2 neurons in the efferent chain from CNS
reflex pathway in gut wall

Question 4

enteroendocrine cells EECs

Answer 4

possess GPCRs (7 TM)
EECs release hormones (GPR119)

Question 5

what is glicentin

Answer 5

GLP1-2 precursor and OXM precursor
in the L cells

Question 6

what are the two major ganglionic networks which form the ENS

Answer 6

outer myenteric plexi (MP)/Auerbach’s plexus

inner sub mucous plexi (SMP)/Meissner’s Plexus

Henly’s plexus

Question 7

MP

Answer 7

controls mostly musculature
contains many different cell bodies/fibres

Question 8

SMP

Answer 8

controls mucosal blood/mucosal function
fewer neuronal types than MP

Question 9

Dogiel classification of enteric nerves

Answer 9

Type I,II,III
starch type IV (SMP)

Question 10

type I

Answer 10

flattened with 4-20 dendrites, 1 long axon - motor (synaptic neurons)
fast epsp

Question 11

type II

Answer 11

angular, star shaped 3-10 longer dendrites
multiaxonal, sensory

after hyperpolarising (AHS) only in ENS, express Ca2+ sensor and K+ channels (IK) IPAN

Question 12

type III

Answer 12

oval cell bodies
2-10 dendrites that ends with ganglion no single function
no ap/AH fast nicotinic synaptic inputs

Question 13

what neurons do MP have

Answer 13

type I,II,III no type IV
low excitability
no AH
TTX sensitive spikes

Question 14

what neurons do SMP have

Answer 14

II, III, IV
no type I

Question 15

neuropeptides

Answer 15

VIP
NPY
CGRP
SOM

Question 16

ENS excitatory NTs

Answer 16

ACh (ChAT)
5HT (5HT3R)
glutamate
ATP(P2XR)

all ligand gated cation channels

Question 17

ENS excitatory neuropeptides

Answer 17

SP
neurokinins (tachykinins)
NKA/NKB - NK1/2/3 (GPCRs)

Question 18

ENS inhibitory NTs

Answer 18

GABA
NO

Question 19

ENS inhibitory neuropeptides

Answer 19

VIP
NPY
galanin
dynorphin (dyn)
enkephalins
somatostatin (SOM)

activate different GPCRs on epithelial and muscles cells

Question 20

small intrinsic contains intrinsic neurons

Answer 20

12>14>2>=4

Question 21

motor neurons

Answer 21

excitatory: ACh, SP(NK1), NKA(NK2),NKB(NK3) (4&6)
inhibitory: GABA,NO,VIP,SOM,NPY (5&7)

Question 22

interneurons

Answer 22

ascending/descending
excitatory and inhibitory
8/9/10

Question 23

sensory neurons

Answer 23

IPANs
cell bodies in MP(2) SMP (11)
release SP,NKA,CGRP

Question 24

secretomotor neurons

Answer 24

12 & 14
release NPY,SOM,dyn+- Ach

Question 25

secretomotor/vasodilator neurons

Answer 25

13

VIP/galanin

Question 26

3 types of IPANs (type II and AH)

Answer 26

mucosal chemoreceptors - stimuli is acid/alkali
mucosal mechanoreceptors - stroking mucosa distorts MP/SMP IPAN- intramural reflex
stretch responsive neurons - distention evoked motility reflexes and secretomotor reflexes

Question 27

GI diseases

Answer 27

cholera and rotavirus infection
Hirschsprung’s disease
diabetes mellitus
enteric neuropathy
IBS/IDS
Chagas disease (destruction of MP along length of gut and gall bladder)

Question 28

symptoms of GI disease

Answer 28

chronic diarrhoea/constipation

Question 29

secretagogues

Answer 29

VIP via UPAC
5HT via 5HT4R

Gs coupled GPCRs stimulate adenylate cyclase

Question 30

anti-secretagogues

Answer 30

PYY and Y1R
Gi coupled GPCR
inhibits AC

Question 31

role of cholera toxin CTX

Answer 31

induced intramural reflex causes electrolyte hypersecretion