Development of the Abdomen

Question 1

What organs are derivatives of the foregut?

Answer 1

Esophagus

Stomach

Proximal half of duodenum

Liver

Gall Bladder

Pancreas

Question 2

What organs are derivatives of the midgut?

Answer 2

Distal half of duodenum

Jejunum and ileum

Cucum and veriform appendix

Proximal 2/3 of transverse colon

Question 3

What organs are derivatives of the hindgut?

Answer 3

Distal 1/3 of transverse colon

Descending and sigmoid colon

Superior 1/2 of rectum

Question 4

Describe the development of the esophagus.

Answer 4

Formed by a partition that develops int he foregut tube called the tracheoesophageal septum

The septum separates two longtidunial tubes that form the trachea (anterior) and esophagus (posterior)

Question 5

Describe the development of the stomach.

Answer 5

Develops as a dilation of the foregut tube, The dorsal surface grows faster and rotates about 90 degrees clockwise

Dorsal surface = greater curavture

Responsible for the formation of the lesser sac

Responsible for vagal trunk composition, anterior - left

Posterior - right

Question 6

Describe the development of the Liver

Answer 6

Develops as the hepatic diverticulum off the forgut

Grows ventrally into the inferior part of the septum transversum

This rapid, ventral growing causes the liver to become suspended by the ventral mesentary between the forgut and anterior abdominal wall

Question 7

Describe the development of the gall bladder

Answer 7

Arise from the hepatic diverticulum

Common stalk of the liver and gall bladder becomes the common bile duct

Question 8

Describe the development of the pancreas

Answer 8

Ventral pancreatic bud arise from the hepatic diverticulum

Dorsal pancreatic develops as a bud off of the dorsal surface of the developing duodenum

Ventral bud duct - main pancreatic duct

Dorsal bud duct - acessory pancreatic duct

Question 9

What two things result from the rotation of the duodenum?

Answer 9

Duodenum becomes C-shaped and ends up to the right of midline

Ventral pancreas and bile duct migrates dorsally

Question 10

What is an annular pancreas?

Answer 10

Rare congenital abnormality characterized by a ring of pancreatic tissue that encircles the descending portion of the duodenum

Can constrict the duodenum and obstruct the intestine

Question 11

Describe the development of the spleen

Answer 11

Forms as an independent condensation of mesoderm between layers of the dorsal mesentery of the stomach

Not an outgrowth of the gut

Question 12

What is physiological umbilical herniation?

Answer 12

Liver and midgut grow so fast that the abdominal cavity is temporarily too small to contain the developing intestines

This causes the intestinal loops to project into the umbilical cord

Question 13

What is gastroschisis?

Answer 13

Ventral body wall defect that results in herniation of intestinal loops into the amniotic cavity

Caused by failure of the body wall to close

Question 14

What is omphalocele?

Answer 14

Ventral wall defect caused when parts of the gut tube that normally herniate into the umbilical cord fail to return to the abdominal cavity

Question 15

What is Meckle’s diverticulum?

Answer 15

A vitelline duct that doesn’t disappear after the midgut returns to the abdomen

Question 16

What is the root of the mesentery?

Answer 16

The attachment of the mesentery of the small bowel that attaches to the posterior wall along a line extending from the upper left to lower right

Question 17

What two things is the fully formed anal canal derived from?

Answer 17

Cloaca and the proctodeum

Question 18

What is the pectinate line?

Answer 18

Separation between the two regions that form the anal canal

Question 19

What is the difference in blood supply and innervation above and below the pectinate line?

Answer 19

Above - inferior mesenteric artery and autonomic innervation

Below - branches if the internal iliac artery and spinal nerve innervation