Abdomen III

Question 1

Describe differences in the peritoneum in males vs females

Answer 1

A ‘closed’ cavity in males
However there is a small gap in peritoneum between the ovary and the Fallopian tube, and this brings an opportunity for infection to spread into the peritoneal cavity. It is also a reason why ectopic pregnancies occur

Question 2

Peritoneum is a thin, serous membrane lining the abdominal and pelvic cavities. 2 types: visceral and parietal. Describe parietal peritoneum

Answer 2

Parietal Peritoneum lines the walls of the abdominal and pelvic cavities

Sensitive to: pain, temp, touch, pressure

Innervated by T7 – L1

Question 3

Peritoneum is a thin, serous membrane lining the abdominal and pelvic cavities. 2 types: visceral and parietal. Describe visceral peritoneum

Answer 3

Visceral Peritoneum lines the abdo and pelvic organs. Sensitive only to: stretch, tearing
Over distension of the viscera leads to pain (e.g. stomach).
Innervated by afferent nerves that travel with autonomic supply, leading to referred pain

Question 4

What is the function of peritoneum and peritoneal folds?

Answer 4

Route of blood vessels, lymphatics, nerves.
May contain embryological remnants
Has diff amounts of fat, eg greater omentum (high volume), lesser omentum (no fat)
May contain intraperitoneal parts of organs; tail of pancreas lies in splenorenal ligament
Immunity and protection: greater omentum=policeman of abdomen. Peritoneum also prevents organ prolapse

Question 5

What are the 2 types of peritoneal folds?

Answer 5

1: folds that connects organs to another organ or to the abdominal wall (omenta, mesenteries, ligaments).
2: folds that are raised from the body wall by underlying blood vessels, ducts and ligaments formed by obliterated foetal vessels. These inc: median, medial and lateral umbilical fold

Question 6

In development, where is the foregut suspended from?

Answer 6

Ventral mesentery/mesogastrium connects the gut tube to the anterior ab. wall
Dorsal mesentery/mesogastrium connects the gut tube to the posterior ab. wall
Mesentery = Double fold of peritoneum

Question 7

Where does the liver start to develop? Label this to help you explain

Answer 7

Liver starts to develop in ventral mesentery. It splits the ventral mesentery into:
Falciform ligament (passing from liver to anterior abdominal wall).
Lesser omentum (passing from liver to stomach).

Question 8

What is the lesser omentum and what does it consist of?

Answer 8

Double fold of peritoneum that connects the liver to the lesser stomach curvature and first part of duodenum. The lesser omentum consists of:
Hepatogastric ligament (see numbered image left)
Hepatoduodenal ligament
Running w/in the hepatoduodenal ligament is the portal triad: C bile duct, proper hepatic artery and hepatic portal vein

Question 9

What happens after the liver is formed?

Answer 9

• Liver then undergoes enormous growth.
• Stomach rotates 90• clockwise. Left side faces anteriorly, right side faces posteriorly
• Stomach rotates around an anteroposterior axis to form a J shaped organ: pyloric part moves to right and upwards. Cardiac part moves to left and downwards
• Dorsal mesogastrium is pulled to left, trapping part of peritoneal cavity behind stomach = Lesser Sac/Omental bursa

Question 10

After the development of the gut tube and the liver, what happens next?

Answer 10

Spleen develops in dorsal mesogastrium dividing it into:
Gastrosplenic ligament (passing stomach to spleen)
Lienorenal ligament (splenorenal) (passing from spleen to left kidney)

Question 11

What is the greater omentum?

Answer 11

Double fold of peritoneum folded back on its self (4 layers), forming an apron structure that hangs from greater curvature of stomach. Policeman of abdomen, has varying degrees of fat
Formed from a downwards extension of the dorsal mesogastrium.
Fused anterior and posterior layers can be surgically separated to give way into the lesser sac through the inferior recess

Question 12

What is the transverse Mesocolon?

Answer 12

A double fold of peritoneum that connects transverse colon to the posterior abdominal wall.

Anterior layer of transverse mesocolon is attached to the posterior layer of greater omentum- so if you pull up the greater omentum you can see it attached.

Question 13

What is the mesentery? Label this

Answer 13

Question 14

What is Omphalocele?

Answer 14

Question 15

What is labelled here?

Answer 15

Question 16

Fill in the blanks

Answer 16

Question 17

What is 1 and 2?

Answer 17

This= mesentry, a fan-shaped double fold of peritoneum that suspends the jejunum and ileum from the posterior abdominal wall.
Contains: Superior mesenteric artery (1) + vein (2)