Flashcards in development of GI Tract Deck (49):
What is the peritoneum?
The innermost layer of the abdominal wall that extends anteriorly, laterally, and posteriorly.
Describe the peritoneum
- It is a continuous glistening and slippery transparent serous membrane.
- It is the largest serous membrane in the body.
- It is loosely connected with the transversalis fascia in most areas.
- Has 2 components: Parietal and visceral
Describe the parietal peritoneum.
Lines the abdominal and pelvic cavities and the abdominal surface of the diaphragm.
- Is loosely connected with the body wall.
- Has the same blood, lymph, and somatic nerves as the wall region above it.
- Innervated by somatic afferent nerves
What is the innervation of the parietal peritoneum?
somatic afferent nerves
o Has many sensory fibers for pain
o Anterior portion is very sensitive to pressure, pain, heat, cold, and lacerations.
describe the visceral peritoneum
Covers the abdominal and pelvic viscera and includes the mesenteries.
- Has the same blood, lymph, and visceral nerves as the underlying tissue.
What is the innervation of the visceral peritoneum
Has NO somatic afferent nervesi
o Is relatively insensitive to pain.
o Can get pain from tension upon or stretching of the tissue or chemical irritation Spinal Cord
o Is insensitive to touch, heat, cold, and laceration.
o Sensory fibers for pain are carried by the thoracic and lumbar splanchnic nerves.
What is the classification of organs in the peritoneum
Secondarily retroperitoneal organs
What are the organs of the intraperitoneal?
Organs almost completely covered with the visceral peritoneum o Stomach, spleen, liver, etc.
What are the organs of the retroperitoneal?
Organs that are covered on 1 surface with visceral peritoneum o Examples: adrenals, kidneys & ureters
What are the organs of the secondarily paritoneal?
Organs that developed as intraperitoneal but migrated to a retroperitoneal position later in development.
o Examples: duodenum, pancreas, major portions of the ascending and descending colon
What are the messenteries?
A double layer of peritoneum that occurs as a result of the invagination by an organ.
- Is a continuity of the visceral peritoneum and the parietal peritoneum.
- Connects an intraperitoneal organ to the body wall.
- Provides means for neurovascular communication between organ and body wall.
- Has a core of connective tissue containing blood and lymphatic vessels, nerves, lymph
nodes, and fat.
What are peritoneal folds?
Reflections of the peritoneum that have sharp borders; they are raised from body wall by underlying blood vessels, ducts, and ligaments formed by obliterated fetal vessels.
What are the peritoneal folds?
Median umbilical fold
Medial umbilical fold
lateral umbilical fold
describe the median umbilical fold.
From apex of urinary bladder to umbilicus
o Covers the median umbilical ligament (remnant of the urachus that joined apex
of fetal bladder to umbilicus)
describe the medial umbilical fold
Lateral to the median umbilical fold (there are 2 of them)
o Covers the medial umbilical ligaments (occluded parts of the umbilical arteries)
describe the lateral umbilcal fold
Lateral to the medial umbilical folds (there are 2 of them)
o Covers the inferior epigastric vessels
describe the ligaments
Double layer sheet or peritoneal fold that connects an organ with another organ or to the abdominal wall.
What are some examples of ligaments
Falciform – Connects liver to anterior abdominal wall.
o Hepatogastric – connects liver to stomach.
o Hepatoduodenal – connects liver to duodenum
o Gastrophrenic – connects stomach to inferior surface of diaphragm. o Gastrosplenic – connects stomach to spleen.
o Gastrocolic – connects stomach to transverse colon.
What is a peritoneal fossa?
Pouch of peritoneum that is formed by a peritoneal fold.
What are the fossae of the anterior peritoneal cavity?
Medial inguinal fossae
Lateral inguinal fossae
Where is the Supravesical fossae?
Between the median and medial umbilical folds
o Where the peritoneum reflects from the anterior abdominal wall onto the bladder
Where is the medial inguinal fossae?
Between the medial and lateral umbilical folds o Also known as the inguinal triangles
Where is the lateral fossae?
Lateral to the lateral umbilical folds
o Include the deep inguinal ring
What are the other fossae of peritoneal cavity?
hepatorenal recess, and
What is the Omentum?
Double-layered extension or fold of peritoneum that passes from the stomach and proximal part of the duodenum to adjacent organs in the abdominal cavity.
What are the Omentums?
describe the Greater Omentum.
Prominent 4-layered peritoneal fold that hangs down like an apron from the greater
curvature of the stomach and the proximal part of the duodenum.
- Folds back and attaches to the anterior surface of the transverse colon and its
- Covers loops of small bowel.
- Blood supply: gastroepiploic arteries, veins drain into the portal system.
- Lymphatics : Right toward the subpyloric nodes, left toward the splenic nodes.
describe the lesser Omentum.
Double-layered entity suspended between the lesser curvature of the stomach and the proximal part of the duodenum to the liver.
- Can be divided into 2 ligaments - hepatogastric and hepatoduodenal.
- Contains the portal triad, branches of the anterior vagus nerve, lymph nodes, and the
right and left gastric arteries.
What is the Peritoneal Cavity?
space between the parietal and visceral peritoneum within the abdominal cavity. In males the peritoneal cavity is completely closed, however in females there is a communication to the outside through the opening of the uterine tubes. It can be subdivided into the greater and lesser sac, or into compartments:
What are divisions of the peritoneal cavity.?
describe the Greater sac.
The main and larger part of the peritoneal cavity.
describe the lesser sac.
The smaller part of the peritoneal cavity also known as the omental bursa.Allows free movement of the stomach on the structures posterior and inferior to it
because the anterior and posterior walls of the sac slide smoothly over each other. o Communicates with greater sac via the omental foramen (epiploic foramen of Winslow), an opening posterior to the free edge of the hepatoduodenal ligament.
What are the boundaries of the lesser sac?
posterior to the stomach and lesser omentum
What are the boundaries of the omental foramen?
Anterior – hepatoduodenal ligament containing portal vein, hepatic artery, and bile
b. Posterior – Inferior vena cava (IVC), right crus of diaphragm, (both retroperitoneal).
c. Superior – Liver.
d. Inferior – 1st part of duodenum.
What are the recesses of the omental foramen?
Superior – Limited superiorly by the diaphragm and posterior layers of the coronary
ligament of the liver.
- Inferior – between the superior parts of the layers of the greater omentum
What are the compartments?
Where is the supracolic compartment?
Above transverse mesocolon. Contains stomach, liver, spleen.
describe the infracolic?
Below transverse mesocolon. Contains small intestines, ascending, and descending colon.
o Lies posterior to greater omentum.
o Is divided into 2 spaces by the mesentery of the small intestine (right and left
o These spaces allow for free communication between the supracolic and
infracolic compartments via the paracolic gutters (grooves between the lateral aspect of the ascending or descending colon and posterolateral abdominal wall.)
What does the pelvic compartment contain?
What happens at the 6th week of gestation?
the midgut grows faster than the abdominal cavity so it prolapses into the umbilical cord.
How does the herniated bowels extend?
from the distal 1/3 of the duodenum to the proximal 1/3 of the transverse colon.
How are they supplied?
branches of the SMA.
What are remnants of the arterial side of the primitive vitelline circulation
to the yolk sac.
Celiac trunk, SMA, and IMA
What happens around the 10 -12th week?
it returns to the abdomen undergoing a 270 degree counterclockwise
￼rotation around the SMA.
Where does the duodenum and proximal small intestines rotate
to the right of the future colon.
What happens to the cranial limb as the intestines return to the abdomen?
the cranial limb returns first so the duodenum passes behind the SMA
What does the caudal limb make up?
the distal ileum and the entire colon
When does the caudal limb return?
Last which bring up the transverse colon in front of the artery and duodenum