Class 2 Flashcards
What is the peritoneum?
A transparent serous membrane that covers the body wall and organs.
Name the 2 subdivisions of the peritoneum and their innervation.
Visceral (autonomic) and parietal (somatic by T7-T12 & L1).
What is the peritoneal cavity and what are its 2 major divisions?
The potential space between the visceral and parietal peritoneum - there are no organs here, only peritoneal fluid. Major divisions are the lesser and greater sacs.
How to the lesser and greater sacs communicate and where is this structure located?
Via the epiploic/omental foramen which is located posterior to the free margin of the lesser omentum.
What is the difference between an intraperitoneal and retroperitoneal organ? Give examples of each.
An intraperitoneal organ is completely covered by visceral peritoneum - stomach, spleen, liver, ileum and jejunum.
A retroperitoneal organ is only covered by peritoneum on its anterior surface and is firmly attached to the posterior wall - pancreas, ascending colon, descending colon and duodenum.
What are the attachments of the greater and lesser omenta?
Greater omentum: from the greater curvature of the stomach to the transverse colon.
Lesser omentum: from the liver to the lesser curvature of the stomach (hepatogastric ligament) and 1st part of the duodenum (hepatoduodenal ligament).
What is the difference between pain from the parietal peritoneum and pain from the visceral peritoneum?
Parietal: this lines the abdominal wall and is innervated by T7-T11 & L1, and so pain here can be precisely localised and is very sensitive to stretch - called rebound tenderness.
Visceral: this lines the actual organ and has somatic innervation, and so pain here is often referred to the midline (due to bilateral innervation).
Which muscles, organs/tubes, main vessels and nerves are on the posterior abdominal wall?
Muscles: psoas major, iliacus and transverse abdominus.
Organs/tubes: kidneys, ureters and pancreas.
Main vessels: abdominal aorta and IVC.
Nerves: lumbar plexus and hypogastric plexus.
Name the 3 major openings in the diaphragm and the vertebral levels at which these occur.
IVC - T8
Oesophagus - T10
Abdominal aorta - T12
What are the 3 major branches of the abdominal aorta, which vertebral levels do they arise and what do they supply?
Celiac trunk - T12 - foregut
Superior mesenteric artery - L1 - midgut
Inferior mesenteric artery - L3 - hindgut
At which vertebral level does the abdominal aorta bifurcate into the common iliac arteries?
L4
What do the L and R common iliac veins join to form in the abdomen?
IVC
Name the structures of the foregut, midgut and hindgut.
Foregut: abdominal oesophagus, stomach, liver, gall bladder, pancreas, spleen and proximal half of duodenum.
Midgut: distal half of duodenum, jejunum, ileum, caecum, appendix, ascending colon and proximal 2/3 of transverse colon.
Hindgut: distal 1/3 of transverse colon, descending colon, sigmoid colon and rectum.
How does venous blood drain from the GI tract?
Via the hepatic portal system - portal systems begin and end in capillaries.
How is the portal vein formed?
By the union of the SMV and IMV.
Where does blood above the diaphragm and below the pelvic floor drain to?
The systemic venous system, meaning that anastomoses are present at these areas.
What are the 4 sites of portocaval/portosystemic anastomoses?
Oesophagus, paraumbilical area, anal canal and bare area of liver (retroperitoneal).
What is the clinical significance of portocaval anastomoses?
In portal hypertension (liver cirrhosis) anastomoses can become congested and form venous dilatations which can lead to: oesophageal varices, caput medusae and rectal hemorrhoids.
Describe the sympathetic nerve supply to the abdominal viscera.
Abdominopelvic splanchnic nerves (greater, lesser and least)
Prevertebral sympathetic ganglia
Abdominal aortic plexuses
Describe the parasympathetic nerve supply to the abdominal viscera.
Anterior and posterior vagal trunks (CNX)
Pelvic splanchnic nerves (S2, S3 and S4)
What is a splanchnic nerve?
A paired visceral nerve (a nerve that contributes to the innervation of internal organs) that carries autonomic fibres (visceral efferent fibres) as well as sensory fibres (visceral afferent fibres).
What is the main difference between the greater, lesser and least splanchnic nerves, and the pelvic splanchnic nerves?
Greater, lesser and least carry sympathetic fibres. Pelvic carry parasympathetic fibres.
Describe vagotomy.
A surgery in which 1 or more of the vagal branches are cut to reduce the rate of gastric secretion.
What are the parasympathetic and sympathetic effects on: gastric secretion, peristalisis/GI motility, and blood vessels?
Parasympathetic - vasodilation
Sympathetic - vasoconstriction
What is the difference between the arrangement of ganglia in parasympathetic and sympathetic systems?
Parasympathetic have long preganglionic fibres and short postganglionic gibres, and synapse close to the target organ.
Sympathetic have short preganglionic fibres and long postganglionic fibres, and synapse in the sympathetic chain or prevertebral ganglia.
What vertebral level do the kidneys lie at on the posterior abdominal wall?
T12 - L3
Why does the right kidney lie lower than the left?
Due to the liver being on the RHS.
What are the 3 main structures entering/leaving the hilum of the kidney (anterior to posterior)?
Renal artery,renal vein and renal pelvis.
What is the suprarenal/adrenal gland?
An endocrine gland - one situated on top of each kidneys.
What are the ureters?
Muscular ducts that carry urine from the kidneys to the urinary bladder.
Name the 3 locations at which the ureters are constricted during their passage from the kidneys to the urinary bladder.
1) At the junction of the ureter and the renal pelvis (pelviuretic junction)
2) As the ureter enters the pelvis and crosses over at the common iliac artery bifurcation
3) At the uterovesical junction as the ureter obliquely enters the bladder wall
How are the kidneys and ureters peritonised?
Both are retroperitoneal.
