8. Peritoneal and GI development 1.pptx Flashcards
What is the difference in the peritoneal cavities of males and females?
Clinical risk?
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
Where is the extraperitoneal tissue found?
Between the parietal peritoneum and the fascial lining of the abdomen and pelvic walls (transversalis fascia)
How is the peritoneal cavity divided?
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
What structures allows free communications between the greater and less omentum?
Epiploic foramen of Winslow
What is the omenta?
Two-layered folds of peritoneum that connect the stomach and 1st part of the duodenum to other
Greater and lesser omentum
What is the greater omentum?
“Policeman of the abdomen”??
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
Lesser omentum:
From where to where?
Other names?
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
Which terms essentially means the same as epiiploic?
Omental
What is the hepatoduodenal ligament?
The free edge of the lesser omentum containing the portal vein, hepatic artery and bile duct
What are mesenteries?
Name the 3 present in the abdomen?
Double-layered peritoneal folds that attach viscera to the posterior abdominal wall
- The mesentery (associated with the small intestine)
- Transverse mesocolon
- Sigmoid mesocolon
What is the The Mesentery?
Which structures does it cross?
Contains branches of which structures?
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
What is the anastomotic arcade difference between the ileum and jejunum?
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
Sigmoid mesocolon:
What is it?
Root?
Transmits which vessels?
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
Transverse mesocolon:
Function?
Root?
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
Which organs are contained in the supra and infra colic compartments?
Supra: Liver, stomach and spleen
Infra: Jejunum, ileum, ascending and descending colon
Which half of the infra colic compartment has…
a paracolic gutter (left and right)
Name the spaces/gutters present within the peritoneum?
Ant right subphrenic space Post right subphrenic space Ant left subphrenic space Right paracolic gutter Left parabolic gutter
Where is the epiploic foramen?
Within the right posterior subphrenic space / hepatorenal recess / Morison’s Pouch
Name the 3 pelvic peritoneal pouches?
- The recto-uterine pounch (in females) separating the rectum from the uterus
- The rectovesical pouch (in males) separating the rectum from the bladder
- The vesico-uterine pouch (in females) separating the bladder from the uterus
Name the 3 umbilical folds and their features?
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
Which structure is truly intraperitoneal?
The ovary
Which structures are retroperitoneal?
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
Which is the difference in the stimuli the the parietal and visceral peritoneum are sensitive to?
Parietal peritoneum: Sensitive to pain, temperature, touch, and pressure
Visceral peritoneum: Sensitive only to stretch and tearing
Which nerves supply the following:
- Peritoneum lining the ant abdominal wall
- Diaphragmatic peritoneum
- Parietal peritoneum in pelvis
- Visceral peritoneum
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
What are the 3 layers of the trilaminar disc? And what does each layer form?
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
What are the stages of GI developement: day 14,17 and 18?
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
What are the 3 stages of embryonic folding in gut tube formation?
- Endoderm is pinched off to form the gut tube and communicates with yolk sac
- Mesoderm moves to what will become posterior abdominal wall
- Lateral folds close body wall and enclose intra-embryonic coelom
What is exophalos?
Failure of intestine to return to abdomen, lies within peritoneum and amnion in umbilical cord.
What is gastroschisis?
Failure of abdominal wall, contents not covered by peritoneum or amnion
The stomach and proximal part of the duodenum have a ventral mesentery, which becomes….
Lesser omentum and falciform ligament
