Digestive System Development

Question 1

oropharyngeal membrane is made up of ______

Answer 1

ectoderm & endoderm

Question 2

gastrulation

Answer 2

establishes the 3 germ layers within the embryo - ectoderm, mesoderm, endoderm

Question 3

All three germ layers contribute to the formation of the digestive system

Answer 3

…

Question 4

ectoderm’s role

Answer 4

neural crest cells from neuroectoderm become neurons of the enteric system

Question 5

mesoderm’s role

Answer 5

connective tissue, muscular components, and peritoneal components

Question 6

endoderm

Answer 6

epithelium of GI tract and parenchyma of glands

Question 7

cranial/caudal folding

Answer 7

sagittal - growth of the head and tail regions that cause the embryo to curve into fetal position - opens the gut tube into the yolk sac narrows - forms a small connection (vitelline) - incorporated into the umbilical cord

Question 8

lateral folding

Answer 8

grows ventrally - consists of the parietal somatic layer and overlying ectoderm - folds meet in the midline & fuse to close ventral body

Question 9

gut tube is divided into 3 regions

Answer 9

foregut, midgut, hindgut

Question 10

foregut

Answer 10

extends from oropharyngeal membrane to liver outgrowth -

Question 11

oropharyngeal membrane

Answer 11

separates the stomodeum from the pharynx

Question 12

midgut

Answer 12

begins caudal to the liver and extends to proximal 2/3 of transverse colon

Question 13

hindgut

Answer 13

from the distal 1/3 of the transverse colon to the cloacal membrane (ectoderm & endoderm form this membrane)

Question 14

mesentery

Answer 14

double layer of peritoneum that encloses an organ and connects it to the body wall

Question 15

intraperitoneal

Answer 15

organs which are completely enclosed in mesentery and connected to wall via mesentery

Question 16

retroperiotneal

Answer 16

organ that lies against the posterior body wall and is covered with periotneum on anterior surface only

Question 17

dorsal mesentery

Answer 17

formed via visceral mesoderm layers and meeting and fusing in midline - suspends the caudal part of the foregut, the midgut, and some of the hindgut

Question 18

divisions of the dorsal mesentery

Answer 18

dorsal mesogastrium, mesoduodenum, dorsal mesocolon, mesentery proper

Question 19

dorsal mesogastrium

Answer 19

greater omentum - dorsal mesentery in region of the stomach

Question 20

mesoduodenum

Answer 20

dorsal mesentery in region of the duodenum

Question 21

dorsal mesocolon

Answer 21

dorsal mesentery in region of the colon

Question 22

mesentery proper

Answer 22

dorsal mesentery of jejunal and ileal loops

Question 23

ventral mesentery is derived from the _______

Answer 23

septum transversum

Question 24

liver divides the ventral mesentery into:

Answer 24

lesser omentum & falciform ligament

Question 25

lesser omentum

Answer 25

extends from lower portion of esophagus, stomach, & upper portion of duodenum to liver

Question 26

falciform ligament

Answer 26

extends from liver to ventral body wall

Question 27

each gut region is supplied by one of 3 major arteries off of abdominal aorta

Answer 27

forgut (celiac trunk) , midgut (superior mesenteric artery), hindgut (inferior mesenteric artery)

Question 28

foregut

Answer 28

blood supply: celiac trunk

Derivatives: esophagus, trachea, stomach, duodenum, liver, biliary apparatus, pancreas

Question 29

foregut divides into:

Answer 29

respiratory primordium & esophagus

Question 30

esophagus

Answer 30

upper 2/3: striated muscle & vagus nerve — lower 1/3 smooth muscle & splanchnic plexus

Question 31

left vagus nerve innervates the

Answer 31

anterior wall fo the stomach

Question 32

the right vagus nerve innervates

Answer 32

the posterior wall of the stomach

Question 33

duodenum is formed from____

Answer 33

the terminal part of foregut and cephalic part of the midgut

Question 34

hepatic cells invade the septum transversum, narrowing the connection between the liver bud and foregut creating the ___

Answer 34

common bile duct - ventral outgrowth forms the gallbladder & cystic duct

Question 35

pancreas is formed by 2 buds

Answer 35

dorsal pancreatic & ventral pancreatic

Question 36

main pancreatic duct (of Wirsung)

Answer 36

formed by the distal part of dorsal duct + ventral duct - with the bile duct, is enters the duodenum at major papilla

Question 37

accessory pancreatic duct (of Santorini)

Answer 37

formed by proximal part of dorsal - enters at MINOR papilla

Question 38

Midgut

Answer 38

Blood supply: SMA - begins just distal to the entrance of bile duct into duodenum - ends at the jxn. of proximal 2/3 transverse colon

Question 39

vitelline duct abnormalities

Answer 39

meckel diverticulum, vitelline cyst, vitelline fistula

Question 40

meckel diverticulum

Answer 40

2-4% - small portion of vitelline duct persists as an outpocketing of the ileum

Question 41

vitelline cyst

Answer 41

both ends of vitelline duct may develop into fibrous cords , with the middle portion forming a large cyst

Question 42

vitelline fistula

Answer 42

vitelline duct remain patent over its entire length, leading to direct communications between the umbilicus & intestinal tract

Question 43

mesentery proper

Answer 43

mesentery of the jejunoileal loops -

Question 44

Hindgut

Answer 44

gives rise to: distal 1/3 of transverse colon, sigmoid colon, rectum, upper part of anal canal - forms internal lining of bladder & urethra - blood supply: IMA

Question 45

cloaca

Answer 45

endoderm lined cavity covered at its ventral boundary by surface ectoderm

Question 46

urorectal septum

Answer 46

wedge of mesoderm that separates the region between the allantois and hindgut

Question 47

superior 2/3 of anal canal derived from

Answer 47

endorderm of hindgut

Question 48

inferior 1/3 of anal canal derived from

Answer 48

invaginating ectoderm