embryology

Question 1

what is the embryonic disk ?

Answer 1

the interface between the amniotic sac and the yolk sac

Question 2

whata are the layers of the embryonic disk ?

Answer 2

ectoderm
mesoderm
endoderm

Question 3

where does the GI tract originally come from ?

Answer 3

endoderm

Question 4

where does the connective tissue and the muscles of the GI tract come from (surrounding structures) ?

Answer 4

from the mesoderm

Question 5

where does the spleen come from ?

Answer 5

mesoderm

Question 6

what is the blood supply associated which of these sections :
foregut
midgut
hindgut

Answer 6

foregut : celiac trunk
midgut : SMA
Hindgut : IMA

Question 7

what are the different derivatives of the foregut, midgut and hindgut ?

Answer 7

foregut : mouth to the ampulla of vater
midgut: ampulla of vater until transverse colon
hindgut: transverse colon to rectum

Question 8

what is the mesentry made up of ?

Answer 8

holds everything in place
double layer of peritoneum

Question 9

what is the difference between intraperitoneal and retroperitoneal organs ?

Answer 9

intraperitoneal are enclosed by the mesentry
retroperitoneal only have the mesentry on their anterior surface and lie posterior against abdominal wall

Question 10

the mesentery comes from ?

Answer 10

mesoderm

Question 11

what are the two types of mesentry ?

Answer 11

dorsal mesentry
ventral mesentry

Question 12

where is ventral mesentry found ?

Answer 12

bottom oesophagus
stomach
upper duodenum

Question 13

where is the ventral mesentry derived from ?

Answer 13

septum transversum ( mesenchyme tissue)

Question 14

what two structures are derived from the ventral mesentry ?

Answer 14

lesser omentum - connects stomach and duodenum from the liver
falciform ligament - connects the liver to the anterior abdominal wall

Question 15

what are thw two types of omentum ?

Answer 15

lesser and greater
greater omentum - hangs from greater curvature of the stomach
lesser - between stomach and liver

Question 16

what is the greater omentum formed from ?

Answer 16

mesogastrium

Question 17

what organ buds off from the foregut ?

Answer 17

the lungs called the respiraatory diverticulum

Question 18

what seperates the respiratory diverticulum from the oesophagus ?

Answer 18

the tracheo oesophageal septum

Question 19

what happens if there is abnormal development in the tracheo oesophageal septum development and how does it happen ?

Answer 19

esophageal atresia happens
this happens when the septum deviated posteriorly

Question 20

what are the three forms of esophagela atresia ?

Answer 20

EA with TEF - most common
pure EA
H type EA

Question 21

what are the clinical features of esophgeal atresia ?

Answer 21

polyhydraminous ( baby cant swallow the amniotic fluid )
drooling , choking and vomiting when the baby is born
a NG tube cannot be passed

Question 22

what are the findings associated with tracheo oesophageal fistulas ?

Answer 22

gastric distention ( air in stomach )
as well as respiratory distress caused by aspiration pneumonia due to reflux

Question 23

what is the treatment and prognosis of EA ?

Answer 23

surgical repair
some residual dismotilyty

Question 24

what is physiologic herniation and when does it happen ?

Answer 24

on the 6th week of development a normal type of herniation occurs through the umbilical cord
reduction of this hernia happens by week 12

Question 25

what happens if physilogic herniation persists ?

Answer 25

persistence results in omphalocele intestines are outaide of the body covered by membrane

Question 26

if the liver is found to be in the sac of the omphalocele what is this an indication of ?

Answer 26

failure of the lateral embryonic folds

Question 27

what are the intestines and midgut in omphalocele covered by ?

Answer 27

peritoneum happens through the umbilical cord

Question 28

what are the genetic defects associated genetic defects ?

Answer 28

trisomy 21 ( down syndrome) trisomy 18 ( edwards syndrome ) trisomy 13

Question 29

what are the associated conditions with omphaocele ?

Answer 29

congenital heart defects orofacial clefts neural tube defects

Question 30

what is the difference between omphalocele and gastroschisis ?

Answer 30

gastrochisis the herniation happens through the a paraumbilical abdominal wall defect not covered by peritoneum as with omphalocele

Question 31

what is the main problem associated with gastroschisis ?

Answer 31

poor GI function

Question 32

what is physiologic rotation of the midgut and what is the normal positioning it ends up in ?

Answer 32

the bowel rotates in week 6-7 around the SMA cecum in the right lower quadrant

Question 33

what are the problems associated with malrotation of the gut ?

Answer 33

obstruction volvulus - wraps around the SMA left sided colon - anatomic variant

Question 34

what is the presentation of volvulus ?

Answer 34

vascular compromise causes ischemia and obstruction hence the vomiting and sepsis

Question 35

what is the vitelline duct ?

Answer 35

like a connector between the yolk sac and the intestines , should disappear during development week 9

Question 36

what are the anomalies associated with the vitelline duct ?

Answer 36

meckels diverticulum ( most common) cysts polyps

Question 37

what type of diverticulum is meckels diverticulum ?

Answer 37

true diverticulum contains all layers of the bowel

Question 38

what are the contents of meckels diverticulum ?

Answer 38

contains all layers of the bowel often contains gastric tissue ectopic gastic tissue

Question 39

what is the rule of 2 associated with meckles diverticulum ?

Answer 39

2 % of the population male to female ratio is 2:1 within 2 feet of the ileocecal valve usually 2 inches in size

Question 40

how is a diagnosis of meckels made and what is the treatment ?

Answer 40

technetium scan capsule endoscopy surgery is the treatment

Question 41

what are the other vitelline duct anomalies ?

Answer 41

cyst sinus - cavity behind umbilicus persistent duct - intestinal discharge from the umbilicus

Question 42

foetus with atresia or stenosis ?

Answer 42

mother has polyhydraminous

Question 43

what is the cause of atresia ?

Answer 43

failure of recanalization

Question 44

what is the associated genetic disorder with duodenal atresia ?

Answer 44

down syndrome

Question 45

what is seen on imaging with duodenal atresia ?

Answer 45

double bubble sign

Question 46

what is the pathology associated with jejunal ileal colonic atresia ?

Answer 46

vascular disruption causing ischemic necrosis

Question 47

what is seen on imaging of jejunal ileal colonic atresia ?

Answer 47

apple peel atresia

Question 48

what is the presentation of pyloric stenosis ?

Answer 48

first born boys are more likely projectile vomiting non bilious vomiting olive palpable mass

Question 49

what is the blood supply of the spleen ?

Answer 49

celiac trunk