Class 2

Question 1

What is the peritoneum?

Answer 1

A transparent serous membrane that covers the body wall and organs.

Question 2

Name the 2 subdivisions of the peritoneum and their innervation.

Answer 2

Visceral (autonomic) and parietal (somatic by T7-T12 & L1).

Question 3

What is the peritoneal cavity and what are its 2 major divisions?

Answer 3

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.

Question 4

How to the lesser and greater sacs communicate and where is this structure located?

Answer 4

Via the epiploic/omental foramen which is located posterior to the free margin of the lesser omentum.

Question 5

What is the difference between an intraperitoneal and retroperitoneal organ? Give examples of each.

Answer 5

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.

Question 6

What are the attachments of the greater and lesser omenta?

Answer 6

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).

Question 7

What is the difference between pain from the parietal peritoneum and pain from the visceral peritoneum?

Answer 7

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).

Question 8

Which muscles, organs/tubes, main vessels and nerves are on the posterior abdominal wall?

Answer 8

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.

Question 9

Name the 3 major openings in the diaphragm and the vertebral levels at which these occur.

Answer 9

IVC - T8

Oesophagus - T10

Abdominal aorta - T12

Question 10

What are the 3 major branches of the abdominal aorta, which vertebral levels do they arise and what do they supply?

Answer 10

Celiac trunk - T12 - foregut

Superior mesenteric artery - L1 - midgut

Inferior mesenteric artery - L3 - hindgut

Question 11

At which vertebral level does the abdominal aorta bifurcate into the common iliac arteries?

Answer 11

L4

Question 12

What do the L and R common iliac veins join to form in the abdomen?

Answer 12

IVC

Question 13

Name the structures of the foregut, midgut and hindgut.

Answer 13

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.

Question 14

How does venous blood drain from the GI tract?

Answer 14

Via the hepatic portal system - portal systems begin and end in capillaries.

Question 15

How is the portal vein formed?

Answer 15

By the union of the SMV and IMV.

Question 16

Where does blood above the diaphragm and below the pelvic floor drain to?

Answer 16

The systemic venous system, meaning that anastomoses are present at these areas.

Question 17

What are the 4 sites of portocaval/portosystemic anastomoses?

Answer 17

Oesophagus, paraumbilical area, anal canal and bare area of liver (retroperitoneal).

Question 18

What is the clinical significance of portocaval anastomoses?

Answer 18

In portal hypertension (liver cirrhosis) anastomoses can become congested and form venous dilatations which can lead to: oesophageal varices, caput medusae and rectal hemorrhoids.

Question 19

Describe the sympathetic nerve supply to the abdominal viscera.

Answer 19

Abdominopelvic splanchnic nerves (greater, lesser and least)

Prevertebral sympathetic ganglia

Abdominal aortic plexuses

Question 20

Describe the parasympathetic nerve supply to the abdominal viscera.

Answer 20

Anterior and posterior vagal trunks (CNX)

Pelvic splanchnic nerves (S2, S3 and S4)

Question 21

What is a splanchnic nerve?

Answer 21

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).

Question 22

What is the main difference between the greater, lesser and least splanchnic nerves, and the pelvic splanchnic nerves?

Answer 22

Greater, lesser and least carry sympathetic fibres. Pelvic carry parasympathetic fibres.

Question 23

Describe vagotomy.

Answer 23

A surgery in which 1 or more of the vagal branches are cut to reduce the rate of gastric secretion.

Question 24

What are the parasympathetic and sympathetic effects on: gastric secretion, peristalisis/GI motility, and blood vessels?

Answer 24

Parasympathetic - vasodilation

Sympathetic - vasoconstriction

Question 25

What is the difference between the arrangement of ganglia in parasympathetic and sympathetic systems?

Answer 25

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.

Question 26

What vertebral level do the kidneys lie at on the posterior abdominal wall?

Answer 26

T12 - L3

Question 27

Why does the right kidney lie lower than the left?

Answer 27

Due to the liver being on the RHS.

Question 28

What are the 3 main structures entering/leaving the hilum of the kidney (anterior to posterior)?

Answer 28

Renal artery,renal vein and renal pelvis.

Question 29

What is the suprarenal/adrenal gland?

Answer 29

An endocrine gland - one situated on top of each kidneys.

Question 30

What are the ureters?

Answer 30

Muscular ducts that carry urine from the kidneys to the urinary bladder.

Question 31

Name the 3 locations at which the ureters are constricted during their passage from the kidneys to the urinary bladder.

Answer 31

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

Question 32

How are the kidneys and ureters peritonised?

Answer 32

Both are retroperitoneal.