Development of the Digestive System

Question 1

the connection b/w the gut and yolk sac during embryonic lateral body folding is known as ?

Answer 1

vitelline duct

Question 2

epithelial lining and the glands of the GI tract are derivatives of what ?

Answer 2

endoderm

Question 3

smooth musculature and conenctive tissue of the GI tract are derivatives of ?

Answer 3

splanchnic mesoderm

Question 4

parietal peritoneum is of what derivative ?

Answer 4

somatic mesoderm

Question 5

visceral peritoneum is of what derivative

Answer 5

splanchnic mesoderm

Question 6

what is the peritoneum

Answer 6

serous membrane lining the abdominal cavity and organs

Question 7

what is a mesentery

Answer 7

double layer of peritoneum that suspends organs from the body wall

Question 8

what is the derivative of dorsal mesentery

Answer 8

splanchnic mesoderm

Question 9

what is the derivative of ventral mesentery

Answer 9

splanchnic mesoderm

Question 10

what type of body folding results in mesenteries

Answer 10

lateral folding

Question 11

which mesentery is split/divided because of the development of the liver

Answer 11

ventral mesogastrium

Question 12

which mesentery becomes the greater omentum

Answer 12

dorsal megogastrium

Question 13

what is the ectodermal contribution to the GI tract

Answer 13

neural crest cells migrate and become the enteric nervous system

Question 14

what are the 3 main divisions of the GI tract, and where are those divisions

Answer 14

foregut - esophagus to mid duodenum
midgut - mid duodenum to proximal 2/3 transverse colon
hindgut - distal 1/3 of transverse colon to asshole

Question 15

what is the basis of how the different regions of the GI tract are divided ?

Answer 15

based upon blood supply

Question 16

what artery supplies the foregut

Answer 16

celiac trunk a.

Question 17

what artery supplies the midgut

Answer 17

superior mesenteric a.

Question 18

what artery supplies the hindgut

Answer 18

inferior mesenteric a

Question 19

all arterial supply to the GI tract are branches off what main artery

Answer 19

dorsal aorta

Question 20

what are some of the foregut derivatives

Answer 20

pharynx, lower resp. system, esophagus, stomach, proximal 1/2 of duodenum

Question 21

what is the special name of the endodermal lung bud on the ventral side of the foregut

Answer 21

respiratory diverticulum or tracheo-bronchial diverticulum

Question 22

what side of the foregut becomes to the greater curvature and what side does it face after curvature

Answer 22

dorsal side, will be on left

Question 23

what type of rotation does the stomach undergo

Answer 23

90 degree clockwise rotation

Question 24

what is the recess behind the stomach created by the 90 degree rotation that allows the stomach to expand during eating

Answer 24

omental bursa

Question 25

what are the organs that are secondarily retroperitoneal (behind the abdominal cavity) ? what causes this to happen ?

Answer 25

duodenum and pancreas | -shifting of stomach 90 CW causes them to turn

Question 26

what endodermal outpouch gives rise to the liver, gall bladder, and bile ducts

Answer 26

hepatic diverticulum

Question 27

what organ develops from 2 seperate endodermal buds, one dorsal and one ventral then eventually fuse

Answer 27

pancreas

Question 28

the unicate process is + inferior portion of the head of the pancreas are derivatives from what bud of the pancreas

Answer 28

ventral bud

Question 29

the main pancreatic duct is made from ?

Answer 29

distal dorsal bud duct + ventral bud duct

Question 30

the accessory pancreatic duct is made form ?

Answer 30

proximal dorsal bud duct

Question 31

what is the condition of annular pancreas

Answer 31

rare condition where ventral bud develops and fuses early causing an obstructive ring around the duodenum = vomiting bile

Question 32

what are some of the midgut derivatives

Answer 32

distal duodenum, jejunum, ileum, cecum, ascending colon, and proximal 2/3 transverse colon

Question 33

what is a physiological umbilical herniation and when does this ovvur ?

Answer 33

temporary herniation of intestines in midgut loop into the proximal umbilical cord around week 6-10 -NORMAL cuz intestines forming faster than body cavity

Question 34

what is congenital omphalocoele

Answer 34

persisting umbilical herniation w/in proximal umbilical cord

Question 35

what is gastrochisis

Answer 35

hernia of small int. that doesnt involve umbilical cord

Question 36

explain how the midgut loop undergoes 270 degree rotation

Answer 36

1st part - 90 degree CCW while midgut loop still in proximal umbilical cord 2nd part - 180 degree CCW rotation as intestines return to abdomen cavity

Question 37

what is the axis of rotation during the rotation of the midgut

Answer 37

superior mesenteric a. (SMA)

Question 38

what parts of the midgut become secondarily retroperitoneal after rotation

Answer 38

ascending colon and descending colon

Question 39

kidneys are primary or secondarily retroperitoneal

Answer 39

primarily meaning developed w/in peritoneal cavity and remained in the peritoneal cavity

Question 40

what is the end result in a case of non rotation of the midgut

Answer 40

Normal 1st rotation BUT NO 2nd rotation - small intestines on right - Lg. intestines on left or Left sided colon

Question 41

what is the end result of a reversed rotation of the midgut

Answer 41

Normal 1st rotation BUT reveresed 2nd rotation | -All in normal posistion EXCEPT duodenum is ventral to transverse colon (usually function normally)

Question 42

what is volvulus and what causes it ?

Answer 42

abnormal rotation of midgut intestinal loop = bowel obstruction leading to multiple disorders

Question 43

stenosis

Answer 43

abnormal narrowing/constriction

Question 44

atresia

Answer 44

abnormally closed or absent lumen

Question 45

fistula

Answer 45

abnormal passageway b/w 2 structures

Question 46

explain recanalization of the midgut loop

Answer 46

intestines are temporarily plugges at week 6 then | RECANALIZE by epithelial cells dying off eventually reforming lumen at week 8

Question 47

what is Meckel's Diverticulum

Answer 47

- most common GI malformaiton (especially males) - vitelline duct persists as fingerlike outpouching of ileum potentially causing a fistula b/w belly button and intestine =shit out of belly button

Question 48

what are the hindgut derivatives

Answer 48

distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, anus

Question 49

the rectum and anal canal are both derivatives of what

Answer 49

cloaca or cloacal membrane

Question 50

what divides the cloacal membrane into seperate urogenital membranes and anal membranes

Answer 50

urorectal septum

Question 51

how is the partitioning of the cloaca into the urogenital sinus and anorectal canals organized on the body

Answer 51

urogenital membrane ventrally | anorectal canal dorsally

Question 52

what is Hirschsprungs disease

Answer 52

-Aganglionic megacolon nueral crest cells fail to migrate and form enteric nervous system -causes constant constriction of bowel cuz no nervous system to relax = blocks colon and severe constipation