9 22 Embriology of the gut tube-Table 1

Question 1

what is the GI tract largly made of

Answer 1

the endoderm

Question 2

what does the endoderm contribute to in the GI?

Answer 2

the epithelial lining of the gut and the epithelial components of the glands

Question 3

what does the mesoderm contribute to in the GI tract?

Answer 3

muslces, connective tissue, mesentaries and mesenchymal components of glands

Question 4

what does the ectorderm contribute to?

Answer 4

epithelium of mouth and anus enteric gagnlia

Question 5

what is the sheet of mesoderm that suspends the gut tube in the middle of the body tube?

Answer 5

the splanchnic mesoderm

Question 6

what lines the primitive gut

Answer 6

the splanchnic mesoderm or the visceral serous membrane

Question 7

what is derived from the visceral serous membrane and extends the lenght of the gut

Answer 7

the dorsal mesentery

Question 8

what does the dorsal mesentery serve for?

Answer 8

the pathway for blood vessels, nerve and lymphatics suppling the GI kltract

Question 9

what are the divisions of the GI tract?

Answer 9

the pharynx; respiratory diverticulum; stomach; liver cords; gall bladder; Midgut; hindgut

Question 10

what provides blood to the stomach

Answer 10

the celiac artery

Question 11

what provides blood to the intestine nearer the stomach

Answer 11

the superior mesenteric artery

Question 12

what provides blood to the hindgut

Answer 12

the inferior mesenteric

Question 13

the gut tube starts out hollow and the cells proliferate and fill the tube, how does it becoem a tube again?

Answer 13

the cells cavitate out again to form a larger but again hollow tube!

Question 14

What can be a possible result of caviation of the gut that goes wrong?

Answer 14

diverticulus, or a stenosis (a small out growth or a narrowing.)

Question 15

how can we get areas of the GI tract that undergo atresia

Answer 15

defective cavitation; malrotation can cuase twisting of the mesentaries, resulting in loss of blood supply and subsequent necrosis of the gut.

Question 16

what is a mesontary

Answer 16

a connective layer of tissue from an organ to the walls of the cavity etc.

Question 17

what is unique for the stomach mesoderm?

Answer 17

there is a ventral mesontary as well as the dorsal mesontary

Question 18

how do we form the stomach

Answer 18

twisting of the tube about 90 degrees, and differential growth on one side of the tube

Question 19

what is volvulus in the stomach

Answer 19

malrotation can result in this, portion of the stomach rotate abnormally, result in abnormal twisting.

Question 20

what can volvulus lead to?

Answer 20

lead to obstruction due to twisting of GI tube, and ischemia due to twisting of the mesenteries and interruption of the blood supply

Question 21

how can malpositioning of the stomach and other organs occur?

Answer 21

from malrotation.

Question 22

if there is a heterotaxia patient what else would you look for?

Answer 22

vascular anomalies

Question 23

what is complete reversal of the left and right sidedness of the organs

Answer 23

Situs Inversus

Question 24

what is partial reversal of the left right orientation of the organs?

Answer 24

heterotaxia

Question 25

organs enclosed in a double layer of peritoneum that connect them to the body wall

Answer 25

intraperitoneal

Question 26

Organs that are not suspended in mesenteries, but lie agains tthe posterior body wall covered by a single layer of peritoneum

Answer 26

Retroperitoneal

Question 27

organs that are intially intraperitoneal and beome retroperitoneal later on due to fusion of hte mesenteries with the posterior wall of the peritoneum

Answer 27

secondarily retroperitoneal

Question 28

Intraperitoneal organs

Answer 28

stomach, transverse colon, small intestines, sigmoid colon

Question 29

Retroperitoneal organs

Answer 29

Thoracic esophagus; rectum

Question 30

Secondarily retroperitoneal organs

Answer 30

duodenum; pancreas; ascending colon; descending colon

Question 31

what is the area of the liver that impacts the diaphram and has no fascia between them

Answer 31

the bare area of the liver

Question 32

Nkx2, Barx1 and Hox11 all affect what?

Answer 32

the spleen and other l/R asymmetric organs early in development.

Question 33

Describe the formation of the pancreus

Answer 33

formation of a dorsal and ventral pancreus, and the ventral will rotate around and drag the hepatic duct with it, and combine with the dorsal pancreatic bud. and make a common duct out.

Question 34

spleen

Answer 34

formed entirely form the dorsal mesogastrium; moves to the the left side as a consequence of stomach rotation

Question 35

what is the early and later on purpose of the spleen

Answer 35

early it is a hemotopoietic organ, but later it is just for lymphatics

Question 36

describe the midgut development!

Answer 36

The midgut herniates to the umbilicus and rotates 90 degrees counter clockwise while doing this. The midgut is then retracted later and does another 180 degree counter clockwise rotation.

Question 37

what does the midgut contribute to?

Answer 37

no adult organs or glands associated with the midgut.

Question 38

what if only the first 90 degree rotation of the midgut happens

Answer 38

then the colon is left out by itself on the left hand side!

Question 39

what if the first rotation in clockwise and no second rotation?

Answer 39

then it looks normal but the duodenum and small intestine traverses over the top of the colon instead of the other way around.

Question 40

what is omphalocele?

Answer 40

where the midgut does not retract and is left in the umbilicus region with amniotic membrane around them

Question 41

Prognosis of omphalocele

Answer 41

can be surgically corrected but look for genetic abnormailites

Question 42

Vitelline connection

Answer 42

the connection to the umbilicus form the ileum.

Question 43

a small diversion of the intestine towards a ligament connected to the umbilicus

Answer 43

meckel’s diverticulum; it is usually asymptomatic

Question 44

small cysts or fistulae from the umbilicus to the intestine that can be painful or infected

Answer 44

vetellin cysts

Question 45

the caudal portion of the gut tube

Answer 45

the cloaca

Question 46

continuous with the allantois

Answer 46

cloaca

Question 47

partition the cloaca to the rectum and urogenital sinus

Answer 47

the urorectal septum

Question 48

rupture of the cloacal membrane creates:

Answer 48

the urogenital sinus and the rectum

Question 49

how to form the anal canal

Answer 49

by cavitation of the ectodermal anal pit, fuses to the rectum at the pectinate line

Question 50

possible problems with the cloaca forming the anus properly

Answer 50

urorectal fistula or rectovaginal fistula where the colon connects to the urethra or vagina;;; rectoperineal fistula where colon connects to the wrong spot in the skin. or the anal membrane doesn’t rupture and no real anus.

Question 51

what embrio layer contributes to the formation of the end of the gut tube?

Answer 51

the ectoderm at the anus.