peritoneum Flashcards
what is the peritoneum?
a continuous transparent membrane which lines the abdominal cavity and covers the abdominal organs (or viscera)
what is the function of the peritoneum?
support the viscera
provides a pathway for blood vessels and lymph
what does the peritoneum consist of?
2 layers which are continuous with each other
outer parietal and visceral (inner) peritoneum
what do both layers of the peritoneum consist of? what is it called?
simple squamous epithelial cells
called mesothelium
what does the parietal peritoneum line?
internal surface of the abdominopelvic wall
what is the parietal peritoneum derived from?
somatic mesoderm in the embryo
what nervous supply does the parietal peritoneum receive?
same somatic nerve supply as the region of the abdominal wall that lines it
how does pain from the parietal peritoneum appear?
well localised
what is the parietal peritoneum sensitive to?
pressure, pain, laceration, temperature
what does the visceral peritoneum cover?
invaginates to cover the majority of the abdominal viscera
what is the visceral peritoneum derived from? (embryo)
splanchnic mesoderm
what is the nerve supply to the visceral peritoneum from?
same nerve supply as the viscera it invests
how is pain from visceral peritoneum perceived?
poorly localised
what is visceral peritoneum sensitive to?
stretch and chemical irritation
where is pain from visceral peritoneum referred to?
area of skin (dermatome) which are supplied by the same sensory ganglia and spinal cord segments as the nerve fibres innervating the viscera
what is the peritoneal cavity?
a potential space between the parietal and visceral peritoneum
what does the peritoneal cavity contain?
small amount of lubricating fluid
how can the abdominal viscera be divided anatomically?
by their relationship with the peritoneum
what are the 2 main groups of the abdominal viscera?
intraperitoneal & retroperitoneal organs
what are intraperitoneal organs?
completely covered in visceral peritoneum, anteriorly & posteriorly
what are examples of intraperitoneal organs?
stomach, liver, spleen
what are retroperitoneal organs?
organs that are only covered in peritoneum on their anterior surface
what are the groups that retroperitoneal organs can be divided into?
2 groups
primary retroperitoneal & secondarily retroperitoneal
what are primary retroperitoneal organs?
organs develop and remain outside of the parietal peritoneum
what are examples of primary retroperitoneal organs?
oesophagus, rectum, kidneys
what are secondarily retroperitoneal organs?
organs initially intraperitoneal, suspended by mesentary
through the course of embryogenesis they became retroperitoneal
with mesentery fusing with posterior abdo wall
peritoneum only covers anterior surface
what are examples of secondarily retroperitoneal organs?
ascending & descending colon
what’s the mnemonic to help recalling which abdominal viscera are retroperitoneal?
SAD PUCKER
what does SAD from SAD PUCKER stand for?
Suprarenal (adrenal) glands
Aorta / IVC
Duodenum (except duodenal cap - first 2cm)
what does PUCKER from SAD PUCKER stand for?
Pancreas (except tail) Ureters Colon (ascending & descending) Kidneys E (Oesophagus) Rectum
what is the peritoneal reflections?
peritoneum develops into a highly folded, complex structure in order to adequately fulfil its functions
(peritoneum covers a multitude of viscera within gut and conveys neurovascular structures from body wall to viscera)
what is the mesentery?
a double layer of visceral peritoneum
connects an intraperitoneal organ to the (usually) posterior abdominal wall
what does the mesentery provide?
a pathway for nerves, blood vessels and lymphatics from the body wall to the viscera
what is the mesentery of the small intestine called?
the mesentery
how is mesentery related to other parts of the GI system named?
according to the viscera it connects to e.g. transverse & sigmoid mesocolons, the mesoappendix
What is the omentum?
a double layer of peritoneum that extends from the stomach and proximal part of the duodenum to other abdominal organs
what does the greater omentum consist of?
consists of 4 layers of the peritoneum
where does the greater omentum extend?
descends from the greater curvature of the stomach and proximal part of the duodenum, then folds back up and attaches to the anterior surface of the transverse colon
what is the role of the greater omentum? what is it sometimes referred to? why?
immunity and is sometimes referred to as the abdominal policeman because it can migrate to infected viscera
what is the lesser omentum and where does it attach to?
smaller than greater
attaches from lesser curvature of the stomach and the proximal part of the duodenum to the liver
what does the lesser omentum consist of?
2 parts: hepatogastric ligament & hepatoduodenal ligament
what is the peritoneal ligament?
a double fold of peritoneum that connects viscera together or connects viscera to the abdominal wall
what is an example of peritoneal ligament? what does it connect?
hepatogastric ligament
connects liver to the stomach
how is pain in viscera identified? why?
poorly localised
as it is 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
what is pain referred according to?
according to the embryological origin of the organ
where is pain from foregut, midgut and hindgut referred to?
pain from foregut structures are referred to the epigastric region, midgut to umbilical, hindgut to pubic region
what does the foregut include?
oesophagus, stomach, pancreas, liver, gallbladder, duodenum (proximal to entrance of the common bile duct)
where foes the midgut extend from and to?
from duodenum (distal to entrance of common bile duct) to the junction of the proximal 2/3rds of the transverse colon with the distal 1/3rd
where does the hindgut extend from to?
from distal 1/3rd of transverse colon to upper part of anal canal
how would pain in retroperitoneal organs present? examples of retroperitoneal organs?
present as back pain
e.g. kidney and pancreas
how would irritation of diaphragm present?
shoulder tip pain
how can irritation of diaphragm occur?
as a result of inflammation of liver, gallbladder or duodenum
how does referred pain in appendicitis appear?
initially pain form the appendix (midgut structure) and visceral peritoneum is referred to the umbilical region
as the appendix becomes inflamed and irritates the parietal peritoneum, the pain becomes localised to the right lower quadrant
how does damage to the peritoneum occur?
as a result of infection, surgery or injury
what can repair to peritoneum result in?
inflammation and repair may cause the formation of fibrous scar tissue
resulting in abnormal attachments between visceral peritoneum of adjacent organs or between visceral and parietal peritoneum
what can peritoneal adhesions from inflammation and repair result in?
pain and complications e.g. volvulus
what is a volvulus?
when the intestine becomes twisted around an adhesion resulting in bowel obstruction
