Feb 26 M1-Embryology Liver, Pancreas and Portal system

Question 1

important thing in gut through development

Answer 1

apoptosis cranial t ocaudal (recanalization)

Question 2

3 main events of gut dev

Answer 2

1. stomach rotation
2. midgut umb herniation: cecum and appendix counterclockwise rotation
3. abdominal counterclockwise rotation

Question 3

2 mechanisms important for recanalization

Answer 3

• genetic

- vascular

Question 4

fatal failure of apoptosis

Answer 4

in biliary tree

Question 5

main duodenal congenital anomalies

Answer 5

• duodenal atresia (distal to major duod papilla)
• duodenal stenosis (distal to major duod papilla)
• intussusception

Question 6

2 causes for duodenum congenital problems

Answer 6

apoptosis failure and bad vascularization (causes failure of apoptosis)

Question 7

consequence of duod atresia or stenosis

Answer 7

polyhyramnios

bilous vomiting in newborn

Question 8

duod atresia or stenosis on radiograph

Answer 8

double bubble sign (air in stomach and in D1 or D2)

Question 9

main cause for duodenal atresia

Answer 9

genetics (associated with trisomy 21) (bad vascularization too leading to failure of apoptosis)

Question 10

cause for duodenal intussusception

Answer 10

poor vascularization.

Question 11

(IMPORTANT) cause for most anomalies in duodenum vs jejunum and ileum

Answer 11

duod: genetics

jejunum + ileum: vascular

Question 12

ventral and dorsal pancr buds formed where + origin

Answer 12

ventral: septum transversum
dorsal: dorsal duodenum
ENDODERMAL in origin

Question 13

origin of exocrine and endocrine cells of the duodenum

Answer 13

endoderm

Question 14

what distinguishes segments of intestine when it’s forming

Answer 14

Hox genes (homeobox genes)

Question 15

critical hox gene defining whole duodenum AND pancreas later

Answer 15

pdx1

Question 16

where and how pancr buds fuse

Answer 16

in clockwise rotation of stomach (foregut rotation). pancreas becomes retroperit

Question 17

structure that rotates with ventral bud

Answer 17

common bile duct (and is placed posterior to D2)

Question 18

in what bud islets of langerhans form

Answer 18

in both

Question 19

last step of pancreas formation

Answer 19

union of the ducts

Question 20

what dorsal pancreatic bud forms

Answer 20

upper head, neck, body tail

Question 21

what ventral pancreatic bud forms

Answer 21

lower head + uncinate process

Question 22

dx sign for duodenum atresia

Answer 22

double bubble sign

Question 23

annular pancreas cause

Answer 23

ventral bud is a bifid structure and not the whole bifid structure goes around at rotation. some stays with bile system = annular pancreas (ring around duod)

Question 24

annular pancreas dx sign

Answer 24

double bubble (+ narrowing on baryum contrast)

Question 25

how portal vein can cause duod obstruction

Answer 25

if goes anteriorly instead of posteriorly, pressure on duod bc carries lot of blood

Question 26

(EXAM) what forms the portal system

Answer 26

vitelline veins

Question 27

(EXAM) what supplies (vascularization) the gut in embryo

Answer 27

vitelline vessels (arteries and veins)

Question 28

(EXAM) what forms drainage of the whole gut

Answer 28

vitelline veins

Question 29

structures crossing uncinate process

Answer 29

SMA and SMV

Question 30

drainage to the liver before the portal vein was defined (before rotation of ventral bud)

Answer 30

2 vitelline veins passing near the 2 pancreatic buds. anastomotic channels between them

Question 31

what determined what formed portal vein

Answer 31

vein and anastomotic way that took was the most direct to the liver = portal vein (remained after foregut rotation)

Question 32

problem of anterior portal vein other than duod obstruction

Answer 32

get 2 portal veins (quadrate instead of triad) bc splenic vein doesn’t fuse with portal vein

Question 33

midgut position as is in umbilicus

Answer 33

proximal midgut to embryo and distal coming back. SMA in between with branches to the 2 parts

Question 34

consequence of umbilical opening too big for midgut

Answer 34

anomalies of rotation + anomalies related to lig of treitz and inferior band

Question 35

rotation of midgut

Answer 35

in umbilicus. 6-10 wks. 90 counterclockwise

Question 36

2 primitive charact of embryo x section at 8 wks

Answer 36

1. endoderm lining (colonic epith and lumen) with cells apoptosing
2. walls of colon vs rest of GIT diff in size

Question 37

colon charact at 8 wks + what will form SM

Answer 37

has differentiated mesenchyme: will form SM

Question 38

what forms Auerbach’s plexus and Meissner’s plexus

Answer 38

NCCs migrating

Question 39

consequence of NCC migration defect

Answer 39

megacolon (no Auerbach’s = no peristalsis)

Question 40

cause of umbilica-body wall transitional area

Answer 40

lateral folding defects

Question 41

2 types of umbilica-body wall transitional area

Answer 41

umb herniation and omphalocele

Question 42

omphalocele def

Answer 42

hole too small for grown intestine to reduce back in abdomen. large prominence there at birth

Question 43

umb herniation def

Answer 43

intestine reduced but hole too big so went back there

Question 44

lining of umb cord in omphalocele vs umbilical herniation

Answer 44

omphalocele = amnion

umb herniation = peritoneum lining

Question 45

omphalocele assoc with what

Answer 45

chromosomal abnormalities

Question 46

gastroschisis def

Answer 46

intestines go in amniotic cavity (NOT in umb cord) through the body wall on side of umb cord. go through abd wall. split abd wall

Question 47

left and right umb veins in embryo which will be more important

Answer 47

left becomes prominent: goes to liver, ductus venosus.

right will regress

Question 48

surface of umbilicus charact

Answer 48

surface ectoderm. skin absent (not developed yet). structure is firm

Question 49

region near umb junction to abd wall charact

Answer 49

single layer of ectoderm on periphery of that

Question 50

where right umb vein regresses

Answer 50

right side of umb junction with abd wall (where single ectoderm layer)

Question 51

gastroschisis cause

Answer 51

unknown