abdominal nerves and the perception of abdominal pain

Question 1

where does the enteric nervous system (ENS) supply

Answer 1

from the oesophagus to the anal canal

Question 2

how many neurons is in the ENS

Answer 2

> 100million

Question 3

arrangement of the ENS

Answer 3

arranged in ganglionic plexuses

interconnecting bundles of UNMYELINATED fibres

Question 4

action of the ENS

Answer 4

can perform reflux actions - secretion, absorption, mixing and gut movements without CNS - basal level
CNS modulates actions of the ENS
axons of intrinsic ENS neurons project to sympathetic ganglia, panc, gall bladder, trachea, spinal chord, brainstem

Question 5

the myenteric plexus

Answer 5

in muscularis - outermost

longitudinal and circular muscle for peristalsis

Question 6

the submucosal plexus

Answer 6

musclularis of the submucosa
secretory gland and sm
muscle contract and relax - move the wall

Question 7

which layer of the gut wall is the ENS in

Answer 7

the submucosal layer

Question 8

purpose of the ANS

Answer 8

involuntary actions

innervate body wall and muscles, abdo and pelvis, head and neck

Question 9

2 divisions of the ANS

Answer 9

sympathetic and parasympathetic

Question 10

where does the ANS originate from

Answer 10

CN 3 7 9 10
(ocularmotor, fascial glossopharyngeal, vagus)
S2-4

Question 11

path of the sympathetic nerves

Answer 11

through the symp chain - the ganglia represent the spinal level

Question 12

path of the parasymp nerves

Answer 12

CN - supply thorax
sacral - supply abdo

mainly

Question 13

function of the ANS to the abdo

Answer 13

efferent - motor to sm, secretomotor to glands (PNS)

afferent - symp: pain, PNS: functional sensation eg stretch

Question 14

where is the coeliac ganglion

Answer 14

around the coeliac axis

Question 15

what does splanchnic mean

Answer 15

visceral

Question 16

sympathetic nerves to the abdomen and their vertebral levels

Answer 16

greater splanchnic - T5-9
lesser splanchnic - T10-11
least splanchnic - T12
nerves from L1-2

all from sympathetic chain

Question 17

autonomic nerve supply to the peripheral vessels and skin

Answer 17

sympathetic only - no PN to body wall
they run with somatic nerves
muscle, sweat glands, erector pili muscles

Question 18

autonomic nerve supply to the organs

Answer 18

lack somatic innervation

nerves run with the arteries to same organs - mostly

Question 19

path of sympathetic nerves from the spinal cord

Answer 19

exit grey matter -> symp chain -> post ganglionic branch

Question 20

how is the ANS supply to the abdo organsised

Answer 20

through plexuses (interconnecting network of nerves) surrounding aorta and branches
symp nerves synapse at ganglia associated with the plexuses
named according to the associated bv

Question 21

name the abdominal plexuses, trunks and ganglia

Answer 21

superior mesenteric ganglion 
inferior ''
symp trunk and ganglion 
inferior hypogastric plexus - below rim of the pelvic inlet 
anterior (L) vagal trunk 
coeliac trunk and ganglion 
renal plexus and ganglion 
superior hypogastric plexus - bifurcation of the abdominal aorta, above rim of the pelvic inlet

Question 22

describe plexuses

Answer 22

the symp and parasymp nerves come together - not combined but in the same network

Question 23

which nerves are associated with which artery

Answer 23

coeliac - X T5-9 
superior mesenteric X T10-11
renal - X T10-12
testicular/ovarian - X T10-11 
inferior mesenteric S2-4 T12-L2
superior and inferior hypogastric plexuses - S2-4 T12-L2

Question 24

where does the sympathetic chain end

Answer 24

the coccygeal segment

Question 25

why is there referred pain

Answer 25

the cerebral cortex has no sensory map for the visceral organs and diaphragm - cannot localiuse sensation from the structures
paoin referred to skin of same dermatome - sympathetic nerves

Question 26

dermatome

Answer 26

area of skin supplied by a single spinal nerve - ie a single segment of the spinal chord
there is no C1 dermatome

Question 27

effect of dermotomes overlapping

Answer 27

at least 3 spinal nerves blocked to = anaesthesia

Question 28

`how is the nerve supply divided

Answer 28

foregut, midgut, hindgut

- have different nerve and blood supply

Question 29

where is epigastric pain from

Answer 29

foregut structures - to the duodenal papilla

stomach, pancreas, liver, proximal duodenum, gall bladder
T7/8

Question 30

where is umbilical pain from

Answer 30

midgut structures - splenic flexure
including inflamed appendix - referred to periumbilical region - colicky - intermittent with bowel contractions

afferent fibres from here enter T10

Question 31

where does the pain go when the inflammation of the appendix has spread to the peritoneum

Answer 31

constant at the R inguinal region
T12-L1
in inguinal fossa
moving of the hip joint and coughing = pain

Question 32

where is suprapubic pain from

Answer 32

hindgut - T12/L2

descending colon to anal canal