peritoneum, peritoneal cavity, stoamch and neurovascular supply to GI system Flashcards
what is the peritoneum?
a continuous membrane which lines the abdominal cavity and covers the abdominal organs (abdominal viscera). it acts to support the viscera and provides pathways for blood vessels and lymph to travel to and from the viscera
what are the 2 layers of peritoneum and what are they made up of?
- parietal and visceral — continuous with each other
- both made up of simple squamous epithelial cells called mesothelium
what lines the internal surface of the abdominopelvic wall?
parietal peritoneum
what is the parietal peritoneum derived from?
somatic mesoderm in embryo
what is the parietal peritoneum sensitive to?
pain (well localised), pressure, laceration and temperature
the parietal peritoneum receives the same _____ supply as the region of the abdominal wall that it lines — therefore pain is _____ from the parietal peritoneum
- somatic
- well localised
what invaginates to cover the majority of the abdominal viscera?
visceral peritoneum
what is the visceral peritoneum derived from?
splanchnic mesoderm in the embryo
the visceral peritoneum has the same _____ supply as the viscera it covers
autonomic
pain from visceral peritoneum?
poorly localised
what is the visceral peritoneum sensitive to?
stretch and chemical irritation
where is pain from the visceral peritoneum referred to?
areas of skin (dermatomes) which are supplied by the same sensory ganglia and spinal cord segments as the nerve fibres innervating the viscera
which peritoenum has somatic/autonomic innervation?
parietal = somatic
visceral = autonomic
what is the only place that the parietal t peritoneum can’t localise?
inferior part of diaphragm — to shoulder - C3/4/5
C3 4 5 KEEPS DIAPHRAGM ALIVE
what is the peritoneal cavity?
a POTENTIAL SPACE between the parietal and visceral peritoneum. it normally contains only a small amount of lubricating fluid
what are intraperitoneal organs covered in?
visceral peritoneum which covers the organ both anteriorly and posteriorly
give examples of intraperitoneal organs
stomach, liver, spleen, appendix, transverse colon
what are retroperitoneal organs covered in?
parietal peritoneum — the peritoneum only covers their anterior surface
what groups can the retroperitoneal organs further be divided into?
> primarily retroperitoneal organs developed and remain outside of the parietal peritoneum. the oesophagus, rectum and kidneys are all primarily retroperitoneal
> secondarily retroperitoneal organs were initially intraperitoneal, suspended by mesenteric. through the course of embryogenesis, they became retroperitoneal as their mesenteric fused with the posterior abdominal wall. thus, in adults, only their anterior surface is covered with peritoneum. examples include the ascending and descending colon
mnemonic for retroperitoneal organs
SAD PUCKER
S - suprarenal (adrenal) glands
A - aorta/IVC
D - duodenum (except proximal 2cm, the duodenal cap)
P - pancreas (except tail)
U - ureters
C - colon (ascending and descending)
K - kidneys
E - oesophagus
R - rectum
describe the mesentery
> double layer of visceral peritoneum
connects an intraperitoneal organ to (usually) the posterior abdominal wall
provides a pathway for nerves, blood vessels and lymphatics to travel from the body wall to the viscera
the mesentery of the small intestine is simply called the ‘mesentery’
mesentery related to other parts of the GI system is named according to the viscera it connects to, eg. the transverse and sigmoid mesocolons, the mesoappendix
what are the omenta?
sheets of visceral peritoneum that extend from the stomach and proximal part of duodenum to other abdominal organs
what does the greater omentum consist of?
4 layers of visceral peritoenum
where does the greater omentum extend from and to?
descends from the greater curvature of the stomach and the proximal part of the duodenum, then folds back up and attaches to the anterior surface of the transverse colon
what is the greater omentum sometimes referred to as?
the ‘abdominal policeman’ — because it has a role in immunity : it can migrate to infected viscera or to the site of the surgical disturbance
what does the lesser omentum consist of?
a double layer of visceral peritoneum
what are the lesser omentum attachments?
lesser curvatures of stomach and proximal part of duodenum to the liver
what are the 2 parts of the lesser omentum?
the hepatogastric ligament (the flat, broad sheet) and the hepatoduodenal ligament (the free edge, containing the portal triad)
what is a peritoneal ligament? example?
a double fold of peritoneum that connects the viscera together or connects viscera to the abdominal wall
eg. hepatogastric ligament, a portion of the lesser omentum, which connects the liver to the stomach
pain in retroperitoneal organs may present as what?
back pain
irritation of the diaphragm (eg. as a result of inflammation of the liver, gallbladder or duodenum) may result as what?
shoulder tip pain
referred pain in appendicitis:
initially, pain from the appendix (midgut structure) and its visceral peritoneum is referred to the ______ region. as the appendix becomes increasingly inflamed, it irritates the _____ peritoneum, causing the pain to localise to the ____________
- umbilical
- parietal
- right lower quadrant
what is this describing?
an organ that is suspended from the body wall by a mesentery
intraperitoneal organ
what is this describing?
a double layer of peritoneum that connects the liver with the lesser curvature of the stomach
lesser omentum
what is this describing?
a double layer of peritoneum that connects the greater curvature of the stomach with the transverse colon
greater omentum
what is this describing?
a double layer of peritoneum that connects an intraperitoneal organ with the body wall
mesentery eg. mesentery, transverse mesocolon, mesoappendix
what is this describing?
the serous membrane that lines the inner surface of the body wall
parietal peritoneum
what is this describing?
the fluid-filled potential space between the parietal and visceral peritoneums
peritoneal cavity
what is this describing?
an organ that is pushed up against the body wall and is only partially covered by peritoneum
retroperitoneal organ
what is this describing?
serous membrane that covers the external surfaces of the abdominal organs
visceral peritoneum
Note that the length of the greater omentum is greater than the distance between the _______ and ___________ so it doubles back on itself forming ____ layers that tend to be fused together. It may contain varying amounts of __ and is often referred to as the “______”
- stomach and transverse colon
- 4
- fat
- fatty apron
what does peritoneal fluid contain?
water, electrolytes, leukocytes and antibodies
if fluid accumulates in the peritoneal space, what condition results?
ascites
what is the peritoneal cavity divided into?
greater and lesser peritoneal sacs
- greater - majority of peritoneal cavity
- lesser (aka; omental bursa) - smaller and lies posterior to the stomach and lesser omentum
the greater sac is divided into 2 compartments by what?
the mesentery of the transverse colon (transverse mesocolon)
describe the supracolic compartment
lies above the transverse mesocolon and contains the stomach, liver and spleen
describe the infracolic compartment
lies below the transverse mesocolon and contains the small intestine, ascending and descending colon. it is further divided into left and right infracolic spaces by the mesentery of the small intestine
what are the supracolic and infracolic compartments connected by?
the paracolic gutters — lie between the posterolateral abdominal wall and the lateral aspect of the ascending and descending colon
The ______ recesses are potential spaces in thesupracolic compartment of the greater sac. They are located between the ________ and the ______. There are left and right ______ spaces, separated by the_______ ligamentof the liver.
The subphrenic recesses are potential spaces in thesupracolic compartment of the greater sac. They are located between the diaphragm and the liver. There are left and right subphrenic spaces, separated by thefalciform ligamentof the liver.
Subphrenic abscesses refer to an accumulation ofpusin theleft or right subphrenic space.They are more common on the______side due to the increased frequency of _________ and ruptured _________ ulcers (pus from the appendix can track up to the subphrenic space via the _________).
Subphrenic abscesses refer to an accumulation ofpusin theleft or right subphrenic space.They are more common on therightside due to the increased frequency of appendicitis and ruptured duodenal ulcers (pus from the appendix can track up to the subphrenic space via the right paracolic gutter).
what does the lesser sac (omental bursa) lie posterior to?
lies posterior to the stomach and lesser omentum
what connects the lesser and greater sacs?
an opening in the omental bursa = epiploic foramen (of Winslow)
what is the epiploic foramen situated posterior to?
the free edge of the lesser omentum (the hepatoduodenal ligament)
lesser sac is the space ________ to the lesser omentum, between the posterior wall of the ________ and the surface of the peritoneum that covers the anterior surface of the _____________
caudate lobe of liver is _______ to the lesser sac
lesser sac is the space posterior to the lesser omentum, between the posterior wall of the stomach and the surface of the peritoneum that covers the anterior surface of the left kidney
caudate lobe of liver is superior to the lesser sac
in what sex is the peritoneal cavity completely closed?
males
what is the rectovesical pouch?
a double folding of peritoneum located between the rectum and bladder
what is the rectouterine pouch (of Douglas)?
double folding of peritoneum located between the rectum and the posterior wall of the uterus
what is the vesicouterine pouch?
double folding of peritoneum between the anterior surface of the uterus and the bladder
how is the peritoneal cavity not completely closed in females? how is this clinically relevant?
the uterine tubes open into the peritoneal cavity, proving a potential pathway between the female genital tract and the abdominal cavity
- clinically therefore infections of the vagina, uterus or uterine tubes may result in infection and inflammation of the peritoneum (peritonitis)
why is the passage of infectious material into the peritoneum in women actually rare?
due to the presence of a mucous plug in the external os of the uterus which prevents the passage of pathogens (but still allows sperm to enter the uterus)
what is this describing?
largest portion of the peritoneal cavity
greater sac
what is this describing?
part of the peritoneal cavity that lies inferior to the liver and anterior to the kidneys and suprarenal gland
hepatorenal recess
what is this describing?
part of the peritoneal cavity inferior to the transverse mesocolon
infracolic compartment
what is this describing?
depression/recess lateral to the descending colon
left paracolic gutter
what is this describing?
smallest portion of peritoneal cavity that lies posterior to the lesser omentum and stomach
lesser sac
what is this describing?
depression/recess lateral to the ascending colon
right paracolic gutter
what is this describing?
part of the peritoneal cavity that lies between the diaphragm and liver
subphrenic space
what is this describing?
part of the peritoneal cavity above the transverse mesocolon
supracolic ligament
identify A-D
what is green, pink, blue?
A = lesser omentum
B = greater omentum
C = transverse mesocolon
D = mesentery
green = supracolic compartment
pink = infracolic compartment
blue = lesser sac
mesentery = a ____ layer of peritoneum that suspends an organ from _____
- double
- the body wall
what are the boundaries of the epiploic foramen?
- anterior = free edge of lesser omentum containing portal vein, hepatic artery and bile duct . hepatoduodenal ligament
- posterior = IVC
- superior = liver
- inferior - first part of duodenum
what supplies blood supply to the foregut/midgut/hindgut?
foregut = coeliac trunk
midgut = superior mesenteric artery
hindgut = inferior mesenteric artery
what provides parasympathetic innervation to the foregut/midgut/hindgut?
vagus nerve = foregut and midgut
pelvic splanchnic nerve = hindgut
foregut sympathetic innervation
preganglionic fibres arise from the lateral horn of spinal cord segments T5-T9 and are conveyed in greater splanchnic nerve. coeliac ganglion
midgut sympathetic innervation
postganglionic fibres arise from superior mesenteric ganglion. lesser splanchnic nerve + least splanchnic nerve, preganglionic arise T10-T11
hindgut sympathetic innervation
fibres conveyed in lumbar splanchnic nerve, inferior mesenteric ganglion, preganglionic fibres arise T12-L1
visceral pain fibres travel with what fibres?
sympathetic fibres
what are the dermatomes of the epigastric region?
T5-T9
where does the foregut extend from and to?
the lower part of the oesophagus to the 2nd part of the duodenum (papilla of Vater)
what is the papilla of Vater?
located where your bile duct and pancreatic duct join and empty into your small intestine
name foregut organs
• gall bladder
• pancreas
• liver
• duodenum proximal to major papilla
• stomach
• spleen
where does the midgut extend from and to?
from the 2nd part of the duodenum to the distal 1/3 transverse colon (just before the splenic flexure)
name midgut organs
• ileum
• jejunum
• hepatic flexure
• appendix
• ascending colon
• caecum
• duodenum distal to major papilla
• proximal 2/3 of distal colon
where does the hindgut extend from and to?
from the distal 1/3 of transverse colon to the proximal part of the anus
name hindgut organs
• proximal part of anus
• descending colon
• sigmoid colon
• splenic flexure
• rectum
• distal 1/3 transverse colon
summarise parasympathetic GIT innervation
vagus nerve = oesophagus to splenic flexure
pelvic splanchnic nerve = splenic flexure to rest of GIT (s2-S4 via hypogastric plexus (doesn’t synapse here) )
parasympathetic vs sympathetic effects on digestion
PS = rest and digest
S = decreases digestion (more blood etc for fight and flight)
stomach functions
• storage of ingested food
• control of chyme entering the duodenum
• protection again invading pathogens
what is anterior, posterior, superior and inferior to the stomach?
anterior = liver, abdominal wall, diaphragm
posterior = spleen, pancreas, transverse colon, left suprarenal land, transverse mesocolon, lesser sac, splenic artery, left kidney
superior = oesophagus
inferior = duodenum
what is the hepatoduodenal ligament?
= free edge of the peritoneal fold that extends between the liver and lesser curvature of the stomach
what does the coeliac trunk come from and where?
from abdominal aorta at T12 (as abdominal aorta enters diaphragm)
what does the coeliac trunk split into?
left gastric, splenic, and common hepatic arteries
what branches does the left gastric artery give off?
oesophageal branches
what branch does splenic artery give off?
left gastroepiploic
what does the common hepatic artery split into?
gastroduodenal and proper hepatic arteries
what does the gastroduodenal artery split into?
right gastroepiploic and pancreatoduodenal arteries
name A-E and its blood supply
A = fundus : short gastric (from splenic artery)
B = lesser curvature (upper) : left gastric
C = lesser curvature (lower) : right gastric (from common hepatic artery)
D = greater curvature (upper) : left gastroepiploic (from splenic artery)
E = greater curvature (lower) : right gastroepiploic (from common hepatic)
what do the right and left gastric veins drain into?
hepatic portal vein
what do the short gastric and left gastroepiploic veins drain into?
splenic vein
what does the right gastroepiploic vein drain into?
superior mesenteric vein
the hepatic portal vein is formed by the union of what?
splenic and superior mesenteric
where is the portal vein formed?
behind the pancreas
lymphatic drainage A-F
A = left gastric
B = short gastric
C = left gastroepiploic
D = right gastroepiploic
E = right gastric
F = coeliac
what lymph nodes receive lymph from the regional nodes of the stomach?
coeliac
visceral pain from the stomach is perceived from what region?
epigastric
preganglionic sympathetic fibres to the stomach arise from what spinal cord segments?
T5-T9
what nerve conveys preganglionic sympathetic fibres for the stomach?
greater splanchnic nerve
the postganglionic sympatheitc fibres from the stomach arise from what ganglion?
coeliac prevertebral ganglion
what nerve conveys parasympathetic fibres to the stomach?
vagus
what expand in the stomach to store food?
rugae
what controls the amount of food released into the duodenum?
pyloric sphincter
A = cardia
B = fundus
C = body
D = pylorus
E = lesser curvature
F = greater curvature
what attaches to the greater and lesser curvatures of the stomach?
greater curvature — greater omentum attaches here
lesser curvature — lesser omentum attaches here
what is the pylorus subdivided into?
pyloric antrum, pyloric canal and pyloric sphincter
A = coeliac trunk
B = common hepatic
C = left gastric
D = splenic
the hepatoduodenal ligament is formed from the free border of the what?
lesser omentum
what structure spass in the hepatoduodenal ligament on route to the liver?
hepatic artery, bile duct, portal vein
what is the median umbilical ligament a remnant of?
urachus
what are the medial umbilical ligaments remnants of?
umbilical arteries
which structure does the lateral umbilical ligaments overlie?
inferior epigastric artery
what does the median umbilical fold extend from and to? what does it overlie?
- from apex of bladder to the umbilcus
- overlies the median umbilical ligament
Lymph from the gut drains first into regional lymph nodes that tend to be associated with the organ. For example lymph from the liver drains into the ______ nodes and lymph from the stomach drains into ______ nodes. Efferent vessels from these regional nodes drain into nodes located around the major vessels. Therefore lymph from foregut structures drains into the ______ nodes, that from midgut structures to the ____________ nodes and that from the hindgut structures into the ___________ nodes.
Lymph from the gut drains first into regional lymph nodes that tend to be associated with the organ. For example lymph from the liver drains into the hepatic nodes and lymph from the stomach drains into gastric nodes. Efferent vessels from these regional nodes drain into nodes located around the major vessels. Therefore lymph from foregut structures drains into the coeliac nodes, that from midgut structures to the superior mesenteric nodes and that from the hindgut structures into the inferior mesenteric nodes.
Into which trunk do the efferent vessels from the coeliac, superior mesenteric and inferior mesenteric nodes drain into?
intestinal trunk
The intestinal trunk empties into the cysterna chyli which is located at the inferior end of which structure?
thoracic duct
Where does the thoracic duct drain into the venous system?
left subclavian vein
Preganglionic sympathetic fibres arise in the _______ horn of grey matter of the thoracolumbar regions of the spinal cord. Their axons pass in the ______ root, spinal nerve, ______ ramus and white ramus communicantes to enter the sympathetic chain. They pass through the chain without synapsing and continue on to the ________ ganglia as ________ nerves. They terminate in prevertebral ganglia by synapsing with the postsynaptic fibres that pass to the effector organ.
- lateral
- ventral
- ventral
- prevertebral
- splanchnic
referred pain : foregut, midgut and hindgut structures?
foregut —> epigastric
midgut —> umbilical
hindgut —> hypogastric
what is the name of the nerve plexus in the muscularis externa?
Myenteric/Auerbach’s plexus
what is the other name for the submucosal plexus?
Meissner’s plexus
