GUT DEV'T. Flashcards
All of the following organs have what in common?
(Stomach, Liver, gallbladder, spleen, 1st part of duodenum, tail of pancreas, jejunum, ileum, appendix, proximal 2/3 transverse colon, sigmoid colon)
Major Peritoneal Organs
All of the following organs have what in common?
Kidney, adrenal gland, ureter, aorta, inferior vena cava, lower rectum, anal canal
Primary Retroperitoneal Organs
All of the following organs have what in common?
Parts 2-4 of duodenum, most of pancreas, ascending colon, descending colon, upper rectum
Secondary Retroperitoneal Organs
Define secondary retroperitoneal organ.
An organ that started as a peritoneal organ but became PARTIALLY covered by parietal peritoneum
What is the role of the mesentery?
A double layer of vascularized tissue that divides parietal peritoneum from visceral peritoneum. It contains dorsal and ventral arteries that supply ALL peritoneal organs.
Explain the significance of the Hepatic Diverticulum.
This is an evagination of the ventral wall of the gut tube into a WIDER ventral mesentery during embryonic gut development.
The tail of the pancreas is a ________ organ, whereas the head of the pancreas is a ________ organ. Which part of the pancreas is more anterior?
Tail is peritoneal organ;
Head is secondary retroperitoneal organ;
The tail is more anterior to the head of the pancreas.
What three structures are contained in the hepatoduodenal ligament?
The portal triad composed of proper hepatic artery (left), common bile duct (right) and portal vein (posterior to both).
What artery runs along the lesser curvature of the stomach? What of the greater curvature?
Lesser stomach curvature - Left gastric artery
Greater stomach curvature - mainly supplied by the Right gastro-omental artery; partly by the left gastric-omental artery
The lesser omentum is made up of what two structures?
The hepatoduodenal ligament (containing the portal triad) and the translucent hepatogastric ligament.
Describe the rotation of the midgut
The midgut rotates 270 degrees across the horizontal (anteroposterial) plane of the SMA, if viewed from the front of the body
Describe the cause and effect of Annular Pancreas.
Some of the pancreas constricts the 2nd part of the duodenum as a result of a defective 180 degree rotation during embryological development.
The pancreas used to have 2 locations in the gut. The ventral portion rotated _____ degrees to fuse with the dorsal part. The dorsal part has the _____ duct whereas the ventral part has the _____ duct, which fuses with the common bile duct to empty via the ________ __ _____.
Ventral pancreas 180 degree rotation;
Dorsal = minor duct, ventral = major duct;
Ampulla of Vater drains into the 2nd part of duodenum.
The spleen is suspended by 2 ligaments. The _____ ligament connects the spleen to the stomach and the _______ ligament has the tortuous splenic artery coursing within it.
Gastrosplenic ligament;
Splenorenal ligament.
How does Omphalocele differ form Gastroschisis?
Omphalocele is caused by a defect in the retraction of the gut in which a portion of the gut is trapped outside the body within the umbilical cord.
Gastroschisis is caused by a defect in the lateral folds of the body wall to fuse, leading to non-function intestines that were EXPOSED to the amniotic fluid.
Secondary retroperitoneal organs are ALWAYS _ ______ of primary retroperitoneal organs. Name at least 4 organs that are secondarily retroperitoneal.
In front of primary retroperitoneal organs;
Most of duodenum, most of pancreas, ascending and descending colon, upper rectum
During weeks 3-4 in the formation of the embryonic gut tube, the _________ plug is supposed to form and apoptosis in the center to form ______.
Epithelial plug;
lumen
A defect in the apoptosis of the epithelial plug can lead to duodenal _____ or ______.
Duodenal stenosis - bilus vomit from little apoptosis
Duodenal atresia - non-bilus vomit from no apoptosis
Describe what a Vitelline Fistula is and how it differs from Ileal (Meckel’s) Diverticulum.
A vitelline fistula comes from the failure to fuse the vitelline duct, where inside contents are EXPOSED to the outside world. An ileal diverticulum is a BLIND-END remnant of the vitelline duct that forms from a failure of the vitelline duct to completely fuse.
Describe the rotation of the foregut and its effects on position of organs. Provide a few examples.
The foregut rotates 90 degrees clockwise along the axis of the gut tube. This positions organs that were once ventral organs on the right side of the body and dorsal organs on the left side.
For example, the liver and lesser omentum that were ventral are now on the right side and the dorsal spleen is on the left side of the body.
How did foregut rotation affect the esophagus?
The esophagus also rotated since it is attached to the stomach, in which the right vagus covers the posterior side and the left vagal plexus covers the anterior side.
Describe the Foramen of Winslow
Winslow’s foramen, also known as the Epiploic foramen, is located on the right side of the body as an opening between the greater sac and lesser sac. It lies under quadrate lobe of the liver.
Describe the features of the quadrate and caudate lobe.
The quadrate lobe is bordered by the gallbladder and the falciform ligament of the liver. Whereas the caudate lobe is located superior to the porta hepatis and looks like a smaller, fin-shaped lobe.
Both the quadrate and caudate lobe are functionally on the left lobe BUT anatomically on the right liver lobe.
Describe the rotation of the midgut and its effect on the position of organs. Provide a few examples of its effect.
Midgut rotation moves the intestines out into the umbilical cord to lengthen, rotates it 270 degrees counter-clockwise along the axis of the SMA and normally retracts it back into the body right after.
This positioned the proximal jejunum on the LUQ and the distal ileum on the RLQ.
Although Gastroschisis ends up with a portion of non-functional intestines, why does omphalocele have a higher mortality rate?
Omphalocele is associated with other genetic defects such as malformation of the heart and kidneys. This explains the higher risk of mortality.
The Left Colic Artery was within the _________ in the embryo but later became ______ ________ in the adult.
Mesentery;
Secondary Retroperitoneal
