Digestive dev

Question 1

time of primitive gut formation

Answer 1

4 weeks

Question 2

name of end of primitive hindgut

Answer 2

cloaca

Question 3

what separates cloaca and proctodeum

Answer 3

cloacal membrane

Question 4

two types of primitive mesentery and types of gut that have them

Answer 4

dorsal - all

ventral - foregut only

Question 5

what does endoderm form in gut

Answer 5

tissue lining the tract and secretory cells

Question 6

what does mesoderm form in gut

Answer 6

smooth muscle, connective tissue, blood vessels

Question 7

time of vitelline duct obliteration

Answer 7

5-6 weeks

Question 8

where does the vitelline duct attach

Answer 8

midgut that will form the illeum

Question 9

what is failure of vitelline duct to close

Answer 9

meckel’s diverticulum, cyst, fistula

Question 10

developments of foregut

Answer 10

resp from larynx to alveoli, eso down to duodenum where meets bile duct

Question 11

8 critical events of foregut development

Answer 11

1. formation of laryngotracheal diverticulum
2. Gastric dilatation
3. elongation of esoph - move stomach to abdo
4. occlusion of foregut on both ends of gastric dilatation by endoderm
5. recanalization of forgut on both ends of gastric dilatation by cavitation
6. shaping the stomach - twist to left
7. differential growth on one side of stomach
8. outgrowth of liver, pancreas, gall bladder

Question 12

developments of midgut

Answer 12

everything the SMA supplies

Question 13

3 critical events of midgut dev

Answer 13

1. elongation of midgut and herniation in midline
2. elongation of proximal half and 90 deg counterclockwise turn
3. return of midgut to abdo cavity - further 180 turn

Question 14

abnormalities of midgut dev (4)

Answer 14

1. malrotation - fine
2. omphalocele - failure to return - lies on umbilical cord
3. gastroschisis - rupture in abdo wall and guts are outside in amniotic fluid
4. umbilical hernia

Question 15

developments of hindgut

Answer 15

everything supplied by IMA + bladder and unrinary system

Question 16

critical events of hindgut development

Answer 16

1. partitioning of cloaca into urogenital and anorectal canals
2. breakdown of anal membrane

Question 17

failure of anal canal to meet proctodeaum

Answer 17

imperforate anus - stenosis or atresia

Question 18

what determines where liver will dev and how

Answer 18

cardiac mesoderm - via blockade of inhibition

Question 19

points of endoderm outgrowth and their developments

Answer 19

1. into dorsal mesoderm - pancreas

2. into ventral mesoderm (septum transversum) - liver, gall bladder, ventral pancreatic bud)

Question 20

contents of fetal gut

Answer 20

meconium

Question 21

consequences of congenital bowel obstruction

Answer 21

1. proximal distension
2. reduced stool output
3. reflux
4. polyhydramnios (no swallowing)

Question 22

causes of congenital obstruction (7)

Answer 22

1. failure to recanalize (duoad and esoph)
2. fetal vascular accident (bowel stroke)
3. congenital pyloric stenosis (too big pyloris)
4. annular pancreas - ring of pancreas
5. congenital volvulus - twisted bowel
6. Intussuseption
7. imperforate anus

Question 23

prevalance of mekels and proportion in men and women

Answer 23

2%

More common in men