Gut and Peritoneum Embryology

Question 1

Define a mesentery. What do they contain?

Answer 1

Double layer of peritoneum that suspends the gut from the posterior body wall.

Contains: fat, arteries, veins, lymphatics, nerves (parsympathetic, sympathetic, visceral afferents)

Question 2

Define intraperitoneal, retroperitoneal, and secondarily retroperitoneal organs.

Answer 2

Intraperitoneal organs are in the peritoneal cavity and have a mesentery.

Retroperitoneal organs developed behind the peritoneum and never had a mesentery.

Secondarily retroperitoneal organs had a mesentery during development, but lost it after they became anchored to the posterior abdominal wall.

Question 3

Which organs are intraperitoneal organs?

Answer 3

Stomach

1st, 4th parts of duodenum and the rest of the small intestine

Cecum

Appendix

Transverse colon

Sigmoid colon

Question 4

Which organs are abdominal retroperitoneal organs?

Answer 4

Kidneys, adrenal glands

Question 5

Which organs are secondarily retroperitoneal?

Answer 5

2nd, 3rd parts of the duodenum

Most of the pancreas (except the tail)

Ascending colon

Descending colon

Rectum

Question 6

Which arteries supply blood to the…

foregut

midgut

hindgut

?

Answer 6

Celiac trunk supplies foregut

SMA supplies the midgut

IMA supplies the hindgut

Question 7

Which organs are part of the foregut?

Answer 7

Everything (including accessory organs) from the abdominal esophagus through the proximal half of the duodenum.

Question 8

Aside from organs in the foregut, which other organ receives its blood supply from the celiac trunk?

Answer 8

The spleen

Question 9

Which organs are considered part of the midgut?

Answer 9

Everything between the distal half of the duodenum through 2/3 of the way down the transverse colon

Question 10

Which organs are considered part of the hindgut?

Answer 10

Everything distal to 2/3 of the way down the transverse colon.

Question 11

Dorsal and ventral pancreatic buds grow off of the ______ to become the _______ and _______ parts of the pancreas, respectively.

Answer 11

buds off the foregut to become the body & tail (dorsal bud) and head (ventral bud), respectively

Question 12

What is the part of the bile duct called where the common bile duct meets the pancreatic duct?

Answer 12

ampulla of Vater

Question 13

Into what section of the duodenum does the ampulla of Vater empty?

Answer 13

The 2nd part, at the major duodenal papilla

Question 14

The dorsal mesentery of the stomach goes on to form the _______ _______, which hangs from the ________ ________ of the stomach.

Answer 14

greater omentum, which hangs off the greater curvature of the stomach

Question 15

In the case of midgut malrotation, where are some possible places where the cecum and appendix could end up (which quadrant)?

Answer 15

Could be in the upper right, or upper left if no midgut rotation occurred.

Question 16

Meckel’s diverticulum is a remnant of the _______ _______.

Describe the “rule of 2s” for this condition.

Answer 16

vitelline duct

2% of population

2 yo at presentation

2x more likely in males

2 feet from the iliocecal junction

2 kinds of ectopic tissue (gastric or pancreatic)

Question 17

The cloaca is divided by the ______ ______. After division, the ventral part will give rise to the ________ ________ and the dorsal part will give rise to the _______ _______.

Answer 17

Urogenital sinus divides the cloaca into the ventral and dorsal parts

Ventral part becomes the urogenital sinus –> bladder, urethra

Dorsal part becomes the anorectal canal

Question 18

The pancreas forms from two pancreatic _____. The uncinate process and main pancreatic duct develop from the _______ ______.

Answer 18

pancreatic buds

uncinate process and main pancreatic duct develop from the ventral bud