The Peritoneum & Peritoneal Cavity Flashcards
What is the peritoneum?
Membrane lining abdominal cavity and encompassing some organs - Parietal peritoneum (around body wall) - Visceral peritoneum (around organs)
What is function of peritoneum?
It acts to support the viscera, and provides pathways for blood vessels and lymph to travel to and from the viscera.
What is the parietal peritoneum derived from?
Somatic mesoderm in the embryo.
What are both layers of peritoneum made up of?
Simple squamous epithelial cells called mesothelium
What is the parietal peritoneum sensitive to?
pressure, pain, laceration and temperature.
Why is pain from the parietal peritoneum well localised?
It receives the same somatic nerve supply as the region of the abdominal wall
What is the visceral peritoneum derived from?
Splanchnic mesoderm in the embryo
What is the visceral peritoneum sensitive to?
Only to stretch and chemical irritation
Describe pain from the visceral peritoneum
Poorly localised –> referred to areas of skin (dermatomes)
Describe the autonomic nerve supply of the visceral peritoneum?
The visceral peritoneum has the same autonomic nerve supply as the viscera it covers
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 can damage to the peritoneum lead to?
The resulting inflammation and repair may cause the formation of fibrous scar tissue. This can result in abnormal attachments between the visceral peritoneum of adjacent organs or between visceral and parietal peritoneum.
Such adhesions can result in pain and complications such as volvulus, when the intestine becomes twisted around an adhesion resulting in a bowel obstruction.
What are intraperitoneal organs?
Enveloped entirely by visceral peritoneum, which covers the organ both anteriorly and posteriorly. Examples include the stomach, liver and spleen.
What are retroperitoneal organs?
Not associated with visceral peritoneum; they are only covered in parietal peritoneum, and that peritoneum only covers their anterior surface.
What are 1ary retroperitoneal organs?
Developed and remain outside of the parietal peritoneum.
E.g. oesophagus, rectum and kidneys
What are 2ary retroperitoneal organs?
Were initially intraperitoneal, suspended by mesentery. Through the course of embryogenesis, they became retroperitoneal as their mesentery fused with the posterior abdominal wall. Thus, in adults, only their anterior surface is covered with peritoneum.
E.g. ascending and descending colon
SAD PUCKER: retroperitoneal organs
S - Suprarenal (adrenal) glands
A - Aorta/IVC
D - Duodenum (except proximal 2cm)
P - Pancreas U: Ureters C: Colon (ascending and descending) K: Kidneys E: (O)esophagus R: Rectum
What is a mesentery?
A double layer of visceral peritoneum that connects an intraperitoneal organ to (usually) the posterior abdominal wall
What is function of a mesentery?
It provides a pathway for nerves, blood vessels and lymphatics to travel from the body wall to the viscera.
What is the mesentery of the SI called? How does this differ from other mesenteries?
‘The mesentery’
Mesentery related to other parts of the GI is named according to the viscera it connects to; e.g the transverse and sigmoid mesocolons, the mesoappendix.
What are the omenta?
Sheets of visceral peritoneum that extend from the stomach and proximal part of the duodenum to other abdominal organs
What does the greater omentum consist of?
Four layers of visceral peritoneum
Where is the greater omentum found?
It 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 does the lesser omentum consist of?
A double layer of visceral peritoneum:
- The hepatogastric ligament (the flat, broad sheet)
- The hepatoduodenal ligament (the free edge, containing the portal triad)
What is a peritoneal ligament?
A double fold of peritoneum that connects viscera together or connects viscera to the abdominal wall.
An example is the hepatogastric ligament, a portion of the lesser omentum, which connects the liver to the stomach.
Where is pain from the:
- Foregut
- Midgut
- Hindgut
structures referred to?
- Epigastric region
- Umbilical region
- Pubic region