GI session 2 Flashcards
peritoneal cavity
potential space between parietal and visceral layers of peritoneum
parietal peritoneum
lines inner surface of abdominal and pelvic wall
subdivisions of peritoneal cavities
greater sac and smaller lesser sac/omental bursa
foramen of Winslow
epiploic foramen. connects greater sac to lesser sac
subdivisions of greater sac
supracolic and infracolic compartment by transverse colon and transverse mesocolon
falciform ligament
double-layered fold of peritoneum
extends from umbilicus onto liver holding a cord-like ligamentum teres in free edge
right layer covers right lobe of liver, reflected onto diaphragm as coronary ligament
left layer encloses the left lobe, reflected onto the diaphragm as the left triangular ligament
lesser omentum
two layers
lesser curvature of stomach, first part of duodenum
right free border - common bile duct, hepatic artery and portal vein
split of omentum
along the lesser curvature, it splits to enclose stomach
along greater curvature, it reforms again as greater omentum
two layers from greater curvature
pass down as anterior two layers of greater omentum and fold on themselves to go upwards and backwards as 2 posterior layers
split of posterior layers of greater curvature
enclose transverse colon and continue onto anterior aspect of pancrease as transverse mesocolon
upper posterior layer of greater curvature
continues as parietal peritoneum of posterior abdominal wall and lining the diaphragm to be reflected back onto liver
lower layer from attachment of transverse mesocolon
continues downwards as parietal peritoneum of lower part of posterior abdominal wall onto pelvic viscera - becomes parietal peritoneum of anterior abdominal wall
where is the parietal peritoneum of the posterior abdominal wall interrupted?
reflected to enclose jejunum and ileum - forming mesentry of small intestine
reflected to enclose sigmoid colon forming sigmoid mesocolon - connects to abdominal and pelvic wall
root of mesentry
line of attachment of mesentery to posterior abdominal wall
where is the parietal peritoneum derived from?
somatic mesoderm
parietal peritoneum innervation
same somatic nerve supply as the region it supplies - pain is well localised. sensitive to pressure, pain, laceration and temperature
where is the visceral peritoneum derived from?
splanchnic mesoderm
visceral peritoneum innervation
same autonomic nerve supply as the viscera it covers. pain is poorly localised. it’s sensitive to stretch and chemical irritation.
pain from visceral peritoneum
dermatomes - areas of skin supplied by same sensory ganglia and spinal cord segments as the nerve fibres innervating the viscera
intraperitoneal organs
enveloped by visceral peritoneum, anteriorly and posteriorly. stomach, liver and spleen
retroperitoneal organs
only covered by parietal peritoneum anteriorly.
primarily retroperitoneal organs
developed and remain outside of parietal peritoneum. oesophagus, rectum and kidneys
secondarily retroperitoneal organs
initially intraperitoneal, suspended by mesentery. became retroperitoneal as mesentry fused with posterior abdominal wall. ascending and descending colon
examples of retroperitoneal organs
suprarenal (adrenal) glands aorta/ivc duodenum pancreas (except tail) ureters colon (ascending and descending) kidneys oesophagus rectum
how does the peritoneum perform its functions?
develops into a highly folded, complex structure
mesentry
double layer of visceral peritoneum. connects intraperitoneal organ to posterior abdominal wall. pathway for nerves, blood vessels and lymphatics. mesentry of small intestine. transverse and sigmoid mesocolons, mesoappendix
omenta
sheets of visceral peritoneum extending from the stomach and proximal parts of the duodenum to other abdominal organs
greater omentum
4 layers of visceral peritoneum. from greater curvature of stomach and proximal part of the duodenum, folds back up and attaches to anterior surface of transverse colon. can migrate to infected viscera or surgical disturbance
lesser omentum
double layer of visceral peritoneum. attaches from lesser curvature of the stomach and proximal part of duodenum to the liver.
peritoneal fluid
water, electrolytes, leukocytes and antibodies. acts as lubricant, allowing free movement of abdominal viscera and antibodies to fight infection.
potential space
when filled with a thin film of fluid, it’s a potential space as excess fluid can accumulate in it - ascites
greater sac
larger portion of cavity. divided into mesentry of transverse colon: supracolic and infracolic compartments
supracolic compartment
above transverse mesocolon. contains stomach, liver, spleen
infracolic compartment
lies below transverse mesocolon. contains small intestine, ascending and descending colon. divided into left and right infracolic spaces by mesentry of small intestine.
how are supracolic and infracolic compartments connected?
paracolic gutters - lie between posterolateral abdominal wall and lateral aspect of ascending or descending colon
lesser sac
omental bursa. lies posteriorly to stomach and lesser omentum. allows stomach to move freely. connected to greater sac through epiploic foramen (posterior to free edge).
where is superfluous fluid most likely to collect?
when sitting or standing up - most inferior portion of peritoneal cavity
rectovesical pouch in males
double folding of peritoneum between rectum and bladder. completely closed.
two pelvic areas of note in females
rectouterine pouch (of Douglas) vesicouterine pouch
rectouterine pouch (of Douglas)
double folding of peritoneum between rectum and posterior wall of the uterus
vesicouterine pouch
double folding of peritoneum between anterior surface of uterus and bladder
enclosure of female peritoneal cavity
uterine tubes open into it.
potential pathway between genital tract and abdominal cavity - infection.
why is infection of peritoneal cavity rare in females?
mucus plug in external os of uterus preventing passages of pathogens - allows sperm.
