8. Peritoneal and GI development 1.pptx

Question 1

What is the difference in the peritoneal cavities of males and females?
Clinical risk?

Answer 1

In males, the peritoneum is a closed cavity, but in females, there is communication with the exterior through the uterine tubes, the uterus, and the vagina

Risk: This may allow the spread of infection from the exterior to inside the peritoneal cavity

Question 2

Where is the extraperitoneal tissue found?

Answer 2

Between the parietal peritoneum and the fascial lining of the abdomen and pelvic walls (transversalis fascia)

Question 3

How is the peritoneal cavity divided?

Answer 3

Into two parts: Greater and lesser sacs

Greater sac: Main compartment and extends from the diaphragm down into the pelvis
Lesser sac: Smaller and lies behind the stomach and lesser omentum but extends slightly into the greater omentum

Question 4

What structures allows free communications between the greater and less omentum?

Answer 4

Epiploic foramen of Winslow

Question 5

What is the omenta?

Answer 5

Two-layered folds of peritoneum that connect the stomach and 1st part of the duodenum to other
Greater and lesser omentum

Question 6

What is the greater omentum?

“Policeman of the abdomen”??

Answer 6

Derived from dorsal mesentery, is a large apron like peritoneal fold.
From greater curvature of the stomach and 1st part of duodenum.
Overlies transverse colon and SI

Named “policeman of the abdomen” as it is drawn to diseased or perforated structures to seal them off

Question 7

Lesser omentum:
From where to where?
Other names?

Answer 7

Passes from the lesser curvature of the stomach an 1st part of the duodenum to the inferior border of the liver.

It may be referred to as hepatogastric and hepatoduodenal ligaments

Question 8

Which terms essentially means the same as epiiploic?

Answer 8

Omental

Question 9

What is the hepatoduodenal ligament?

Answer 9

The free edge of the lesser omentum containing the portal vein, hepatic artery and bile duct

Question 10

What are mesenteries?

Name the 3 present in the abdomen?

Answer 10

Double-layered peritoneal folds that attach viscera to the posterior abdominal wall

1. The mesentery (associated with the small intestine)
2. Transverse mesocolon
3. Sigmoid mesocolon

Question 11

What is the The Mesentery?
Which structures does it cross?
Contains branches of which structures?

Answer 11

A fan shaped double-layered fold of peritoneum that connects the jejunum and ileum to the posterior abdominal wall.
It’s base starts at L2 and pass obliquely downwards to just above the right sacroiliac joint

It crosses the 3rd part of the duodenum, the aorta and IVC, the right gonadal vessels and right ureter

It contains branches of the SMA and SMV, with nerves and lymphatics

Question 12

What is the anastomotic arcade difference between the ileum and jejunum?

Answer 12

The SMA branches as a series of anastomotic arcades.

Jejunum: Has few arcades with long vasa recta
Ileum: Has many arcades with short vasa recta

Question 13

Sigmoid mesocolon:
What is it?
Root?
Transmits which vessels?

Answer 13

Sigmoid mesocolon is the double-layered fold of peritoneum that connects the sigmoid colon to the posterior abdominal wall.

Root: In the left iliac fossa, crossing the bifurcation of the left common iliac vessels and the left ureter

Transmits: The sigmoid branches of the inferior mesenteric vessels plus nerves and lymphatics

Question 14

Transverse mesocolon:
Function?
Root?

Answer 14

The transverse mesocolon suspends the transverse colon from the posterior abdominal wall
Root: Just inferior to the pancreas and it carries branches of the middle colic vessels

Question 15

Which organs are contained in the supra and infra colic compartments?

Answer 15

Supra: Liver, stomach and spleen

Infra: Jejunum, ileum, ascending and descending colon

Question 16

Which half of the infra colic compartment has…

Answer 16

a paracolic gutter (left and right)

Question 17

Name the spaces/gutters present within the peritoneum?

Answer 17

Ant right subphrenic space
Post right subphrenic space
Ant left subphrenic space
Right paracolic gutter
Left parabolic gutter

Question 18

Where is the epiploic foramen?

Answer 18

Within the right posterior subphrenic space / hepatorenal recess / Morison’s Pouch

Question 19

Name the 3 pelvic peritoneal pouches?

Answer 19

1. The recto-uterine pounch (in females) separating the rectum from the uterus
2. The rectovesical pouch (in males) separating the rectum from the bladder
3. The vesico-uterine pouch (in females) separating the bladder from the uterus

Question 20

Name the 3 umbilical folds and their features?

Answer 20

The median umbilical fold contains the urachus, which extends from the urinary bladder to the umbilicus
The medial umbilical folds are raised by the obliterated umbilical arteries, extending from the internal iliac arteries to the umbilicus
The lateral umbilical folds are raised by the inferior epigastric arteries, extending from the deep inguinal rings on each side to the arcuate lines

Question 21

Which structure is truly intraperitoneal?

Answer 21

The ovary

Question 22

Which structures are retroperitoneal?

Answer 22

Primarily retroperitoneal: 
– urinary 
adrenal glands 
kidneys 
ureter 
bladder 
– circulatory 
aorta 
inferior vena cava 
– digestive 
oesophagus (final part) 
rectum (middle 1/3)

Secondarily retroperitoneal:
– the head, neck, and body of the pancreas
– the duodenum, except for the proximal first segment, which is
intraperitoneal
– ascending and descending portions of the colon

Question 23

Which is the difference in the stimuli the the parietal and visceral peritoneum are sensitive to?

Answer 23

Parietal peritoneum: Sensitive to pain, temperature, touch, and pressure

Visceral peritoneum: Sensitive only to stretch and tearing

Question 24

Which nerves supply the following:

• Peritoneum lining the ant abdominal wall
• Diaphragmatic peritoneum
• Parietal peritoneum in pelvis
• Visceral peritoneum

Answer 24

Peritoneum lining the ant abdominal wall: T7 -12 and L1
Diaphragmatic peritoneum: Phrenic nerves C3,4,5
Parietal peritoneum in pelvis: Obturator nerve L2,3,4
Visceral peritoneum: Autonomic afferent nerves that supply the viscera

Question 25

What are the 3 layers of the trilaminar disc? And what does each layer form?

Answer 25

The neural tube and body wall are derived from the ectoderm

The cardiovascular, and musculoskeletal systems, and the body cavities (coeloms) are derived from mesoderm

The gastro-intestinal, respiratory and reproductive tracts are derived from endoderm

Question 26

What are the stages of GI developement: day 14,17 and 18?

Answer 26

Day 14: Trilaminar disc formation

Day 17: Notochord burrow from primitive node, between ecto and endoderm, undergoes a series of developmental changes. Becomes a plate that induces the overlying ectoderm to become a neural plate.
The mesoderm cavities to form the coeloms. In the abdomen this intra-embryonic coelom becomes the peritoneal cavity

Day 18: Cephalo-caudal and lateral folding of trilaminar disc. Creates:

• Endodermal tube of pharynx and oesophagus
• Stomach and intestinal tract
• Glands associate with the GI tract

Question 27

What are the 3 stages of embryonic folding in gut tube formation?

Answer 27

1. Endoderm is pinched off to form the gut tube and communicates with yolk sac
2. Mesoderm moves to what will become posterior abdominal wall
3. Lateral folds close body wall and enclose intra-embryonic coelom

Question 28

What is exophalos?

Answer 28

Failure of intestine to return to abdomen, lies within peritoneum and amnion in umbilical cord.

Question 29

What is gastroschisis?

Answer 29

Failure of abdominal wall, contents not covered by peritoneum or amnion

Question 30

The stomach and proximal part of the duodenum have a ventral mesentery, which becomes….

Answer 30

Lesser omentum and falciform ligament