Digestive System Development I&II

Question 1

where does most of the GI derive from?

Answer 1

endoderm

Question 2

what controls the regional differentiation?

Answer 2

sonic and indian hedgehog - SHH, IHH

Question 3

intraperitoneal vs retroperitoneal surgery

Answer 3

intraperitoneal less invasive

• require less cutting
• faster recovery time

Question 4

what happens with hypertrophy of the falciform ligament?

Answer 4

underdeveloped liver and will not have Barr area –> caught under diaphragm causing respiratory problems

Question 5

effects of Doral mesentery problems?

Answer 5

cannot anchor stomach or develop greater omentum

Question 6

blood supply of foregut?***

Answer 6

celiac trunk

Question 7

what occurs with fast proliferation of epithelial cells of esophagus?

Answer 7

can narrow esophagus causing atresia or stenosis

Question 8

stomach rotation

Answer 8

dorsal border grows faster to become greater curvature & rotates 90 degrees

• lesser curvature to right, greater curv. to left
• left vagus (anterior wall); right vagus (posterior wall)

Question 9

duodenum development

Answer 9

formed from foregut and midgut

• beginning part –> celiac trunk
• inferior part –> SMA
• rotate to right w/ stomach

Question 10

difference b/w child who’s epithelium did not undergo apoptosis in esophagus vs one who’s did not in duodenum?**

Answer 10

esophagus –> trapped food

duodenum –> inhibition of digestion

Question 11

midgut development

Answer 11

midgut herniates into umbilical cord & begins rotation beginning of 6th week
-GI tract grows faster than abdominal cavity

Question 12

what happens during malroation of midgut?**

Answer 12

can impinge on SMA –> ishemia to midgut

Question 13

what is the hindgut supplied by?

Answer 13

IMA

Question 14

what does the cloaca differentiate into in humans

Answer 14

urogenital sinus, anus, and rectum

Question 15

hemorrhoids

Answer 15

• internal hemorrhoids –> nonpainful, rectal bleeding, dark red blood
• external hemorrhoids –> painful, bright red blood

Question 16

where is midgut pain associated with?

Answer 16

umbilical region

Question 17

stenosis

Answer 17

abnormal NARROWING of lumen

• result of incomplete recanalization or hypertrophy of adjacent structure
• hypertrophic pyloric –> projectile vomiting
• duodenum –> vomit includes bile

Question 18

atresias

Answer 18

abnormal CLOSING of lumen

• always by failure of recanalization/apoptosis
• esophageal –> from polyhydroamnios mothers
• duodenal –> premies, Down syndrome, polyhydroamnios mothers, vomitus bile
• extrahepatic biliary –> jaundice 2-6 weeks after birth

Question 19

different atresias

Answer 19

• atresia before stomach –> vomit undigested milk
• atresia of duodenum before bile duct opening –> vomit digested milk w/o bile
• atresia of duodenum after bile duct opening –> vomit digested milk w/ bile

Question 20

annular pancreas

Answer 20

2 parts of ventral pancreatic duct grow and fuse with dorsal pancreatic duct –> atresia or stenosis to duodenum either before or after bile duct opening

Question 21

congenital omphalocele

Answer 21

failure of umbilical ring closure (mesenchymal defect)

-intestines found herniated in umbilical cord

Question 22

umbilical hernia

Answer 22

similar to omphalocele, not as severe

• intestines do not protrude into umbilicus
• protrude only when coughing or crying only

Question 23

gastroschisis

Answer 23

intestines grow outside body –> protrude through hole near umbilical cord

Question 24

midgut non rotation

Answer 24

small intestine on right side, large intestine on left

• organs not where they are suppose to be
• volvulus twisting of SMA –> midgut ischemia
• ex. appendicitis symptoms but appendix not where its suppose to be

Question 25

mixed rotation and volvulus

Answer 25

-cecum below pylorus –> duodenal obstruction

Question 26

reversed rotation

Answer 26

SMA can compress transverse colon –> stenosis

-stenosis of transverse colon and reduced blood flow through SMA

Question 27

subhepatic cecum and appendix

Answer 27

cecum does not separate from liver

-can cause appendicitis –> appendectomy

Question 28

internal hernia

Answer 28

intestinal loop passes through mesenteric defect –> obstructed or strangled
-ex. part of duodenum herniated and trapped behind mesentery wall

Question 29

midgut volvulus

Answer 29

twisting of midgut over duodenum –> obstructed duodenum

-sometimes bile, sometimes not

Question 30

omphaloenteric duct remnant

Answer 30

ductal remnants that develop into cysts in umbilicus

• large cysts –> obstruction of GI
• may persist as vitelline artery
• associated with sirenomelia

Question 31

ileal (meckel) diverticulum

Answer 31

outpouching of ileum w/ vitelline duct/yolk sac remnant

• dark feces, upper GI bleed, obstruct, volvulus
• mimic appendicitis
• diverticulitis if food gets stuck

Question 32

Hirschsprung disease

Answer 32

congenital megacolon
-failure of neural crest cells to migrate –> no autonomic ganglion cells in myenteric plexus –> no peristalsis –> feces stuck in colon

Question 33

anorectal birth defects

Answer 33

• imperforate anus - higher in females

- failure of urorectal septum to separate urogenital from anorectal regions