GIT blood and nerve supply Flashcards
viteline system originates from
the yolk sac
4 groups of embryonic get vasculature
- aortic arches
- vitalise system
- umbilical system
- cardinal veins
viteline system function
to deliver nutrient rich blood to the heart
unpaired arteries come from
splanchnic LP-mesoderm
unpaired arteries start off as being
bilateral, then move toward the midline as the umbilical cord starts to get formed
as folding occurs and the umbilical cord is formed
the unpaired arteries are fused - single dorsal aorta
paired abdominal aortic branches
foregut - coeliac trunk
midgut - superior mesenteric
hindgut - inferior mesenteric
the unpaired aortic branches define
define the developmental gut segments
coeliac artery
found around the aortic hiatus of diaphragm
has three branches each with three further branches
3 primary branches of the coeliac trunk
- left gastric
- splenic
- common hepatic
three branches of the eft gastric branch
left gastric
oesophageal
accessory hepatic
three branches of the splenic branch of the coeliac trunk
splenic
short gastric
left gastro-epiploic
three branches of the common hepatic branch of the coeliac trunk
gastroduodenal
right gastric
hepatic proper
three branches of the gasproduodenal branch of the common hepatic branch of the coeliac trunk
right gastro-epiploic
supra duodenal
superior pancreatic duodenal
three branches of the hepatic proper branch of the common hepatic branch of the coeliac artery
L hepatic
R hepatic
Cystic
lesser omentum of the ventral mesentery of the forget
right and left gastric arteries
hepatoduodenal of the ventral mesentery of the foregut
- proper hepatic artery
- portal vein
- common bile duct
dorsal mesenteries
spleno-renal
gastro-splenic
greater omentum
superior mesenteric artery
midget
found just above the duodenum
6 branches of the superior mesenteric artery
inferior pancreaticoduodenal jejunal branches ileal branches ileocolic right colic middle colic
inferior mesenteric artery
hindgut
closer to aortic bifurcation
3 branches of the inferior mesenteric artery
- left colic
- sigmoid
- superior rectal
watersheds
occur at gut junctions
if the marginal artery doesn’t fuse together - areas supplied by two different arteries
fusion point may not get blood flow
may become necrotic or become narrowed
anastomoses
an alternative route/ssupply
jejunum branches
short arcades, long vasa recta
ileal branches
long arcades, short vasa recta
intraperitoneal artery of the midgut
the mesentery proper
middle colic - proximal 2/3 transverse mesocolon
organs of the portal system are supplied by
paired aortic arteries
derived from viteline veins
functions of the portal system
high nutrient blood passes through the liver before the heart for 1st pass processing
reabsorbed products back to the liver - recycling
portal vein length
a few cm long
union of superior and mesenteric veins
common that all 3 major veins going at the same place
porto-caval anastomoses
of portal resistance is too high, blood is forced in other directions
areas where organs can drain from the gut tube straight into systemic circulation without going through the hepatic system
porto-caval anastomoses are found
at the start and finish of the gut tube
caudal oesophaguss via azygous veins
recto-anal junction via middle and inferior rectal veins
para-umbilical anastomoses
if the liver has a lot of pressure, the blood may be prevented from draining through the liver
blood from the liver empty back toward the umbilicus via the small veins around it that drain the skin
called caput medusae due to presence of visible veins
bare areas
drain to retroparitoneal organs via veins of the body wall, or renal veins
gut autonomic nervous system parasympathetic
splanchopluere only
increase blood flow to gut
increase gut, gall bladder and duct mortality
increase glandular secretions
autonomic parasympathetic nerves
vagus nerve - foregut and midgut
pelvic splanchnic nerves - midgut
vagus nerve
thoracic, foregut and midgut
enters abdomen on either side of the oesophagus
pelvic splanchnic nerves
supply hindgut and pelvic organs
gut autonomic nervous system sympathetic
innervates splanchnopleure and somatopluere
reduced gut function
white rami communicans
none in cervical or below L2
only exist between T1- L1
foregut nerve of the ANS sympathetic system
coeliac ganglion (greater)
midgut nerve of the ANS sympathetic system
superior mesenteric ganglion
hindgut nerve of the ANS sympathetic system
inferior mesenteric ganglion
visceral pain
referred pain
referred to dermatomes where sympathetic nerve derived from
dull poorly defined aches felt over entire dermatome
somatic pain
pain felt locally on body wall when affected organ touches it
sharp and specific
phrenic nerve C3-5 referred pain
irritation form organs coming into contact with the diaphragm
eg. heart, liver, gallbladder
pain felt over dermatomes C3-5
