Embryo

Question 1

Derivatives of Endoderm

Answer 1

Epithelium (except mouth and anal canal)

Question 2

Mesoderm

Answer 2

Splanchnic

Smooth mm. And CT

Question 3

Ectoderm

Answer 3

Mouth and anal canal

Question 4

Neural Crest

Answer 4

ANS

Question 5

Foregut

Answer 5

Pharynx/derivatives
Respiratory system
Esophagus
Stomach
Liver/pancreas
Biliary apparatus 
Proximal duodenum

Question 6

Midgut

Answer 6

Small intestine
Cecum/appendix
Ascending colon
R. 1/2 transverse colon

Question 7

Hindgut

Answer 7

L. 1/2 transverse colon
Descending colon
Sigmoid colon
Rectum
Superior anal canal
Epithelium of urinary bladder/urethra

Question 8

Foregut vessel

Answer 8

Celiac Trunk

Question 9

Midgut vessel

Answer 9

SMA

Question 10

Hindgut vessel

Answer 10

IMA

Question 11

Skeletal muscle of esophagus

Answer 11

Pharyngeal arches 4 & 6

Question 12

Smooth muscle of esophagus

Answer 12

Splanchnic mesoderm

Question 13

LARP (stomach development/rotation)

Answer 13

Left Anterior

Right Posterior

Question 14

Hypertrophic Pyloric Stenosis

Answer 14

Hypertrophy of circular and some longitudinal muscles in the pylorus
Presentation:
- Post-feeding (nonbilious) projectile vomiting
- Few stools
- Fail to gain weight
*Possible olive-like mass @ L1

Question 15

Pancreas (dorsal primordia)

Answer 15

Body
Tail
Part of Head

Question 16

Pancreas (ventral primordia)

Answer 16

Head
Unicate process
(Main duct is from ventral duct)

Question 17

Pancreatic Rotation

Answer 17

When duodenum rotates right, ventral pancreatic bud goes dorsally

Question 18

Annular Pancreas

Answer 18

When ventral bud becomes bifed and rotates to the left to fuse with dorsal bud around 2nd part of duodenum
**Can lead to obstruction in duodenum (with bilious vomit)

Question 19

Midgut Rotation

Answer 19

Leaves abdominal cavity for umbilicus @ W6 (returns @ W10)
Rotates 90* in umbilical cord (then another 180* in return) (Total 270* rotation)

SMA herniates out into umbilical cord @ W6 (liver grows too much)
Returns @ W10 when body has grown enough

Question 20

Omphalocele

Answer 20

W10
Failure of bowel to return to body cavity
*not an umbilical hernia

Question 21

Gastroschisis

Answer 21

W4 Failure of anterior ab. Wall to close

Question 22

Hirschsprung’s Disease

Answer 22

Absence of ganglion cells (d/t failure of Neural crest migration)
Leads to mega colon (d/t loss of motility, feces get “stuck”)

Question 23

Congenital Diaphragmatic Hernia

Answer 23

Herniation of abdominal organs into thoracic cavity

D/t failure of diaphragmatic components to fuse properly

Question 24

Nonrotation of Midgut

Answer 24

SI sits on right side
LI on left side
Side-by-side

Question 25

Reversed Rotation of Midgut

Answer 25

Duodenum become anterior to transverse colon (possible colon obstruction)

Question 26

Meckel’s Diverticulum

Answer 26

Abnormality of Vitelline duct (it normally regresses) Causes a projection from ileum to abdominal wall Rule of 2s - 2 year olds - 2 inches long - 2x more likely in M vs. F - 2 types of ectopic tissue (gastric and pancreatic) - 2% population - 2 ft. From IC Jxn

Question 27

Urorectal Septum

Answer 27

Grows toward cloacal membrane Divides into urogenital membrane and anal membrane Composed of Endo/ectoderm (no mesoderm because we need to open it up)

Question 28

Anal Canal

Answer 28

Superior portion from Hindgut | Inferior portion from proctodeum

Question 29

Superior Anal canal

Answer 29

Upper 2/3 Blood: IMA Nerves: ANS Lymph: Inf. Mesenteric LNs

Question 30

Inferior Anal Canal

Answer 30

Lower 1/3 Blood: middle/inf. Rectal aa. Nerves: Pudendal n. (Somatic) Lymph: Sup. Inguinal LNs

Question 31

Anorectal Malformations

Answer 31

Occur if Endo/ectoderm do not meet up properly | Septum should migrate and separate the cloaca

Question 32

Pleura-peritoneal Membrane

Answer 32

Septum Transversum meets with pleuroperitoneal membranes (somatic layer of lateral plate)

Question 33

Diaphragm Formation

Answer 33

Septum Transversum (central tendon) Pleuroperitoneal membranes Dorsal mesentery of esophagus (cruras)

Question 34

Congenital Diaphragmatic Hernia

Answer 34

Results from defective formation/fusion of pleuroperitoneal membranes Opening in foremen of Bochdalek (most on Left side) Associated with hypoplastic lungs/polyhydramnios

Question 35

Peritoneal Cavity

Answer 35

Mesentery is double layer of serous membrane Dorsal mesentery- attaches to posterior wall Ventral mesentery- attaches to anterior wall *Splanchnic Mesoderm

Question 36

Dorsal Mesocardium

Answer 36

Degenerates leaving the transverse pericardial sinus

Question 37

Dorsal mesogastrium

Answer 37

Greater Omentum (4 total layers) Splenorenal l. Gastrosplenic l.

Question 38

Ventral Mesogastrium

Answer 38

Lesser Omentum

Question 39

Ventral Mesentery

Answer 39

Falciform L.

Question 40

Mesoduodenum

Answer 40

Mesentery around duodenum

Question 41

Mesentery proper

Answer 41

Mesentery containing jejunum and ileum

Question 42

Mesocolon

Answer 42

Mesentery around transverse colon and sigmoid colon

Question 43

Mesorectum

Answer 43

Mesentery around rectum

Question 44

Thoracic Esophagus and Anus

Answer 44

RETROPERITONEAL

Question 45

Intraperitoneal Structures

Answer 45

``` Stomach Tail of pancreas 1st part of duodenum Jejunum Ileum Transverse colon Sigmoid colon ```

Question 46

Retroperitoneal Structures

Answer 46

Pancreas (except tail) Ascending/Descending colon Duodenum (2,3,4th parts)