GI tract Flashcards
length of oesophagus
about 25 cm
muscle of oesophagus
upper 1/3 = skeletal
lower 2/3 = smooth
start of oesophagus
C6/7 at upper oesophageal sphincter
route of oesophagus
posterior to trachea, tracheal bifurcation and left atrium
passes through diaphragm at T10
associated with vagus nerves
stomach start point
abdominal oesophagus enters stomach in the cardia region = upper oesophageal sphincter
about T10
parts of stomach
entry with oesophagus = cardia rounded bit to right = fundus main body greater curvature around the right and lesser curvature to the left pyloric antrum and canal at base
parts of pyloric region
antrum, canal sphincter
greater omentum and stomach
attaches the stomach to the transverse colon
lesser omentum and stomach
attaches the stomach and duodenum to the liver
pyloric stenosis
narrowing of pylorus, food can’t enter duodenum
projectile vomiting, found early in children
gastric ulceration
loss of protective mucus surrounding stomach tissue
acid breaks down stomach tissue
can be caused by the infection helicobactor pylori
sphincter of duodenum with stomach
pyloric sphincter
spinal levels of duodenum,
L1-3
position of duodenum with peritonum
first part is mobile, attached to the lesser omentum
remainder is retroperitoneal
entry of pancreatic and bile duct into duodenum
enter in descending part
flow controlled by sphincter of oddi
anchoring of duodenojejunal junction
anchored by suspensory ligament of duodenum to right diaphragmatic crus
parts of the oesophagus
cervical (starts at level of cricoid), thoracic (mediastinum), abdominal (after diaphragm)
liver divisons
4 anatomical lobes
separation of liver lobes
anterior = R/L lobes separated by the falciform ligament posterior = fissure of ligamentum teres/venosum
names of liver lobes
right, left, caudate, quadrate
position of liver
RUQ
superior = diaphragm, inferior = costal margin
what is the porta hepatis
entry/exit point for the hepatic portal vein, bile duct and hepatic artery
blood supply to liver
hepatic artery and hepatic portal vein provide blood flow to liver
drain to the hepatic vein into the IVC
bile formation
formed in the liver
secreted via bile ductules into right and left hepatic ducts
hepatic ducts join at porta hepatis to form the common hepatic duct
gall bladder function
stores and concentrates bile
connected to common hepatic duct by cystic duct, which from the common bile duct
bile drain into duodenum
pancreatic duct and common pile duct join the second part of the duodenum at the ampulla of vater
what does the free edge of the lesser omentum contain
common bile duct, hepatic artery and hepatic portal vein
pancreas position in peritoneum
retroperitoneal
parts of pancreas
head, body, tail
pancreas and duodenum
pancreatic head within the duodenal curvature, neck behind duodenum, tail in contact with spleen
pancreatic duct
combines with common bile duct to enter the duodenum
enters at the major duodenal papilla
small intestine parts
duodenum
jejunum = surrounded by mesentery, numerous mucosal folds
ileum = enters into the caecum, suspended by mesentery (narrower than other regions)
anatomical relationship of stomach
anterior = abdominal wall, diaphragm, left lobe of liver posterior = separated by sac from pancreas, left kidney and gland, spleen, aorta, transverse colon superior = diaphragm
sotomach innervation
celiac plexus T6-T9 = sympathetic nerves (via greater splanchnic nerve)
vagus is parasympathetic
duodenum innervation
supplied with blood vessels
sym = coeliac and superior mesenteric plexus
para = vagus
jejunum and ileum position
jejunum = umbilical ileum = hypogastric and pelvis
mesentery and small intestine
carries blood vessels, autonomic fibres and lymphatic vessels
starts at duodenal - jejunal junction, attaches most to posterior abdominal wall
jejunum and ileum innervation
parasym and sym in the myenteric and submucosal plexus
parasym = vagus
sym = coeliac plexus via sympathetic trunks and greater splanchnic nerves
large intestine parts
begins at ileo-caceal junction
caecum, ascending colon, trasnverse colon, descending colon and sigmoid colon
large intestine smooth muscle layers
inner circular and outer longitudinal layers of smooth muscle
distinguishing features of large intestine
taeniae coli (3 flattened, thick, muscular bands that run across the entire wall of the caecum and colon) haustrae (pouches of mucosa between the taenia coli) epiploic appendices (fat filled pouches on the outer surface)
caecum position
right iliac fossa
over ilacus and psoas
projects downwards at the start
peritoenum but no mesentery
appendix position
variable around caecum
most lie behind
appendix structure
devoid of taeniae coli, blind ended tube
appendicitis
usually bacterial infection
pain = visceral peritoneum, back to T10 dermatome
typically pain at mcburneys point (1/3 between ASIS and belly button)
mesentery in colon
attached to transverse and sigmoid, so both intraperitoneal
rectum features
begins at S3
retroperitoneal
follows the curve of the sacrum
ano-rectal junction
where the rectum passes posterior and inferior to pass through the pelvic floor muscles
anal sphincters
internal = smooth, autonomic external = striated, pudendal nerve (sym)
large intestine innervation
parasym = mostly vagus, distal = pelvic splanchnic nerves sym = T10-L2, lumbar sympathetic chain and the superior hypogastric plexus
blood supply to foregut
coeliac trunk
where does the coeliac trunk come from
abdominal aorta, just underneath diaphragm at T12
branches of coeliac trunk
left gastric, splenic, and common hepatic arteries
left gastric supplies
oesophagus and anterior/posterior stomach
splenic artery supplies
across posterior abdominal wall to supply the spleen an pancreas, also produces all gastric arteries for the stomach
also branches into left gastroepiploic artery
common hepatic artery divides into
right gastric, gastro-duodenal and hepatic
right gastric artery supplies
anterior/posterior stomach
hepatic artery supplies
liver
gastroduodenal artery supplies
duodenum (first part)
venous drainage of the foregut
follows arteries
drains into hepatic portal or one of the derivatives
venous draining of the stomach
gastroepiploic and short gastric veins drain into splenic vein or superior mesenteric -> portal vein
portal vein produced from
superior mesenteric and splenic veins
inferior mesenteric drain into splenic
position of portosystemic anastomoses
end of oesophagus wall of upper anal canal umbilicus bare area of liver retroperitoneal
what does obstruction of the portal vein cause s
anastomoses vessels widen
get portal hypertension which produce varicose veins on the abdominal wall
splenic vein drains
spleen
stomach fundus
part of pancreas
superior mesenteric vein drains
small intestine, caecum, ascending and transverse colon, distal parts of stomach
inferior mesenteric artery drains
descending colon, rectum and sigmoid
liver and gall bladder blood supply
coeliac trunk -> common hepatic artery
common hepatic artery divides into the hepatic and then cystic and R/L hepatic arteries
cystic -> gall bladder (usually branch of right hepatic)
R/L hepatic -> liver
blood supply to pancreas
at the border for foregut/midgut so both coeliac and superior mesenteric
coaelic trunk -> splenic and superior pancreatic/duodenal arteries
superior mesenteric -> inferior pancreatic/duodenal artery
superior mesenteric artery originates
abdominal aorta about L1
branches of superior mesenteric
inferior pancreatic duodenal
jejunal branches
ileal branches
ileocolic artery -> appendicular and R/L colic
superior mesenteric artery supplies
distal duodenum
jejunum and ileum
colon up to 2/3 along transverse - to SPLENIC FLEXURE
what are the arterial arcades
series of anastomosing arterial arches between the jejunum and ileum
nearest duodenum = primary loops, vasa recta are long
towards ileocolic artery = secondary and tertiary loops
inferior mesenteric origniates
about L3
branches of inferior mesenteric
left colic, sigmoid and super rectal branches
inferior mesenteric supplies
ascending colon, sigmoid colon and superior part of rectum
splenic flexure to rectal-anal junction
what are the marginal vessels
anastaomosis between superior and inferior mesenteric
also called artery of Drummond
continuous arterial circle along the inner border of the coloin
control of gut arterial supply
controlled by sympathetic nerves
vasoconstrictor neurons with cell bodies win the paravertebral and pre vertebral ganglia
lymphatic drainage of abdomen and pelvis
reaches the lumbar and intestinal lymphatic trunks, unite at the cistern chyli forming the thoracic duct
GI tract lymph drains into
superior and inferior mesenteric lymph nodes
retroperitoneum drains into
lumbar lymph nodes
stomach lymph nodes
follow the lesser and greater curvatures
embryo into the gastric, gastroomental and pyloric lymph nodes -> celiac lymph nodes
small intestine lymph nodes
junta intestinal
intermediate mesenteric
superior mesenteric
what vessels to lymph vessels follow
arteries
large intestine lymph vessels
each part has its own nodes
all drain into superior mesenteric
descending and sigmoid colon into inferior mesenteric nodes
liver and gall bladder lymph nodes
cystic and hepatic nodes
sequence of drainage of lymph
all lymph drains into the intestinal trunks, then the cisterna chyli and then the thoracic duct
sympathetic innervation to gut
celiac, superior mesenteric and inferior mesenteric ganglia from T6-L2 spinal nerves
celiac ganglion supplies
stomach blood vessels liver and bile duct pancreas adrenal gland small intestine
superior mesenteric ganglion supplies
small intestine
large intestine
inferior mesenteric ganglion supplies
distal large intestine kidney bladde rectum gonads
parasympathetic nerve supply
vagus to vast majority of organs
S2-S4 supply to hind gut (distal large intestine, rectum, anus)
afferent fibres of the gut
general visceral afferent fibres
conduct sensory impulses from internal organs to CNS
afferent fibres pathway
accompany sympathetic efferent
travel from organ to ganglion, along a splanchnic nerve, into the sympathetic trunk and then into a ventral ramus and the mixed spinal nerve
goes into the dorsal root ganglion
afferent fibres also found in
vagus nerve