Abdomen: Peritoneum Flashcards
What is the Peritoneum?
The Peritoneum is a serous membrane (mesothelium) that lines the abdominopelvic cavity and invests the viscera (organs).
(Simple Squamous Epithelium)
Compare & contrast innervation of the Parietal & Visceral peritoneum
Parietal:
- Same somatic nerve supply as the region of the wall it lines
- Sensitive to pressure, pain, temperature, and laceration
- Well-localized pain-supplied by the same somatic n. supply
Visceral:
- General Visceral Afferent (GVA) pain fibers that travel with the nerves that bring sympathetic innervation to the visceral structure it covers.
- GVA Pain fibers are activated by stretching & chemical irritation
- Insensitive to touch, temp, and laceration
- Poorly localized pain referred to the dermatomes of the spinal levels from which the sympathetic supply originates.
What is meant by Intraperitoneal, Retroperitoneal, & Extraperitoneal?
Intraperitoneal: Located almost completely enclosed by visceral peritoneum
Retroperitoneal: Organs are external to the Parietal Peritoneum and only partially covered with peritoneum.
Extraperitoneal: Organs are external to the Parietal Peritoneum and only partially covered with peritoneum.
Which organs are on the posterior abdominal wall, behind the peritoneum? (Retroperitoneal)
“SAD PUCKER”
S: Adrenal Gland ? *
A: Aorta/IVC
D; Duodenum
P: Pancreas (except Tail)
U: Ureters
C: Colon (Acending & Descending)
K: Kidneys
E: Esophagus
R: Rectum
What are Peritoneal Ligaments?
How are they generally named?
Double layer of peritoneum that connects an organ with another organ or the abdominal wall
The nomenclature is usually descriptive of which structures are attached to each other
What are the functions of the peritoneum?
- Pain perception (parietal)
- Visceral lubrication
- Fat Storage
- Wall off infections (greater omentum)
- Fluid & Particulate Absorption
Describe the Lesser Omentum
The Lesser Omentum is peritoneum stretching between the lesser curvature of the stomach and the visceral surface of the liver.
Subdivisions:
- Hepatogastric lig.
- Hepatoduodenal lig.
Describe the Greater Omentum
The Greater Omentum is an apron-like specialization of peritoneum attaching along the greater curvature of the stomach.
Describe the Epiploic/Omental Foramen.
The Epiploic/Omental Foramen is a passage way between the greater and lesser peritoneal sac, located posterior to the hepatoduodenal lig.
Whats are the mesenteries?
Structure? Function?
Mesenteries are double layered peritoneum resulting from invagination of the peritoneum by an organ, thereby connecting the (now) intraperitoneal organ to the body wall.
It provides a pathway for neurovascular structures to reach the organ from the posterior wall.
What are the mesenteries described in the abdominal cavity? (4)
Abdominal Mesenteries:
- Mesentery of the Small Intestine
- Transverse Mesocolon
- Mesoappendix
- Sigmoid Mesocolon
Describe the Mesentery of the Small Intestine.
The Mesentery of the Small Intestine is a broad fan-shaped fold of peritoneum connecting the loops of jejunum and ileum to the posterior abdominal wall.
Includes the root of the mesentery
Describe the Transverse mesocolon
The Transverse mesocolon connects the transverse colon to the posterior abdominal wall.
Forms the floor of the lesser peritoneal Sac*
Describe the Mesoappendix
The Mesoappendix is a fold of peritoneum around the vermiform appendix, attached to the mesentery of the small intestine. Usually it extends to the tip of the appendix.
Contains:
- Appendicular a. & v.
Describe the Sigmoid Mesocolon
The Sigmoid Mesocolon connects the sigmoid colon to the posterior abdominal wall.
Contains:
- branches of the Inferior mesenteric a. (IMA) travel to the sigmoid mesocolon.
