Peritoneum & Peritoneal Cavity Flashcards
(32 cards)
What is the peritoneum made up of ?
A serous membrane consisting of a single layer of squamous epithelium (mesothelium) that lines the abdominal cavity and covers abdominal organs. It has two layers: parietal (lines the body wall) and visceral (covers the organs).
What are the two layers of the peritoneum, and how do they differ?
Parietal layer: Derived from somatic mesoderm, lines the body wall.
Visceral layer: Derived from splanchnic mesoderm, covers the organs.
Both layers are continuous and separated by peritoneal fluid.
What is the difference between intraperitoneal and retroperitoneal organs?
Intraperitoneal: Organs completely covered by peritoneum (e.g., stomach, liver, jejunum).
Retroperitoneal: Organs partially covered and fixed to the posterior abdominal wall (e.g., kidneys, pancreas, ascending/descending colon).
What is the function of the greater omentum?
Stores fat.
Provides insulation.
Contains macrophages to limit infection spread.
Acts as the “policeman of the gut.”
What structures are found in the free margin of the lesser omentum?
The portal triad: hepatic artery proper, common bile duct, and portal vein.
What are the boundaries of the omental foramen (of Winslow)?
Anteriorly: Hepatoduodenal ligament (with portal triad).
Posteriorly: Inferior vena cava and right crus of the diaphragm.
Superiorly: Caudate lobe of the liver.
Inferiorly: Superior part of the duodenum.
What are the subdivisions of the peritoneal cavity?
Greater sac: Main compartment surrounding most organs.
Lesser sac (omental bursa): Behind the stomach and lesser omentum.
Communicates with the greater sac via the omental foramen.
What are the peritoneal recesses, and why are they clinically significant?
Recesses: Spaces formed by peritoneal folds (e.g., duodenal, caecal, intersigmoid).
Significance: Sites where internal herniation or fluid collection (e.g., ascites, pus) can occur.
How is the parietal peritoneum innervated, and what type of pain does it produce?
Innervation: Segmental supply by intercostal and lumbar nerves (localized pain).
Phrenic nerve supplies the central tendon (referred pain to the shoulder).
What is the clinical significance of the falciform ligament?
Contains the ligamentum teres (obliterated umbilical vein).
Site of porto-systemic anastomosis (paraumbilical veins).
What are the umbilical folds, and what structures do they cover?
Median fold: Covers the urachus.
Medial folds: Cover umbilical arteries.
Lateral folds: Cover inferior epigastric vessels.
What are the key differences between male and female pelvic peritoneum?
Male: Rectovesical pouch between rectum and bladder.
Female: Vesicouterine pouch (anterior) and rectouterine pouch (posterior, aka pouch of Douglas).
What is ascites, and what can cause it?
Ascites: Abnormal fluid accumulation in the peritoneal cavity.
Causes: Cirrhosis, infections (peritonitis), malignancy, or heart failure.
Name three peritoneal ligaments and their attachments.
Falciform ligament: Connects liver to diaphragm/anterior abdominal wall.
Gastrosplenic ligament: Connects stomach to spleen.
Lienorenal ligament: Connects spleen to left kidney.
What is the difference between primarily and secondarily retroperitoneal organs?
Primarily retroperitoneal: Organs that never had a mesentery (e.g., kidneys, adrenal glands).
Secondarily retroperitoneal: Organs that lost their mesentery during development (e.g., most of the duodenum, pancreas).
What is the subphrenic space, and why is it clinically important?
A subdivision of the supracolic compartment between the diaphragm and liver.
Clinical significance: Site for pus collection (subphrenic abscess) post-abdominal surgery or infection.
What structures form the stomach bed?
Posterior relations of the stomach:
Left dome of diaphragm, spleen, left kidney/adrenal, pancreas, transverse mesocolon, and splenic artery/vein.
What is the hepatorenal recess (Morison’s pouch), and why is it significant?
A peritoneal recess between the liver and right kidney.
Significance: Most dependent part of the supine abdominal cavity; fluid collects here (e.g., blood, ascites).
What are the paracolic gutters, and how do they facilitate fluid spread?
Grooves lateral to the ascending/descending colon.
Right gutter: Communicates with the hepatorenal recess and pelvis.
Left gutter: Closed superiorly by the phrenicocolic ligament; drains to the pelvis.
What is the intersigmoid recess, and where is it located?
A peritoneal recess near the sigmoid mesocolon.
Location: Posterior to the sigmoid colon, where the mesocolon attaches to the posterior abdominal wall.
What is the ligamentum teres hepatis, and what is its embryological origin?
fibrous remnant of the umbilical vein (fetal circulation).
Located in the free edge of the falciform ligament.
How does the innervation of visceral peritoneum differ from parietal peritoneum?
Visceral peritoneum: No somatic afferents; pain is referred (e.g., distension, ischemia).
Parietal peritoneum: Supplied by somatic nerves (localized pain, e.g., peritonitis).
What is the porto-systemic anastomosis near the falciform ligament?
Paraumbilical veins (around ligamentum teres) connect the portal vein with systemic veins (e.g., epigastric veins).
Clinical relevance: Dilates in portal hypertension → caput medusae.
What is the gastrosplenic ligament, and what structures does it contain?
A peritoneal fold connecting the stomach to the spleen.
Contains: Short gastric arteries and left gastroepiploic vessels.
