T11- Digestive system development

Question 1

When does the primative gut tube form?

Answer 1

During the 4th week with longitudinal and transverse folding

Question 2

What are intraperitoneal organs

Answer 2

Organs in the peritoneal cavity that are suspended by mesenteries

Question 3

What are retroperitoneal organs

Answer 3

organs that are positioned between the peritoneum and musculature of the posterior body wall

Question 4

What is the greater omentum

Answer 4

double layer of peritoneum that drapes inferiorly from the greater curvature of the stomach and proximal duodenum

Question 5

What is the lesser omentum

Answer 5

A double layer of peritoneum that connects the lesser curvature of the stomach and proximal duodenum to the liver

Question 6

Dorsal mesentery in embryo

Answer 6

attatches primative gut tube to the dorsal abdominal body wall of the embryo from foregut to hind gut

Question 7

Ventral mesentery in embryo

Answer 7

attaches only the foregut to the ventral abdominal body wall of the embryo

Question 8

Derivative of dorsal mesogastrium

Answer 8

greater omentum

Question 9

Derivatives of ventral mesogastrium

Answer 9

lesser omentum and falciform ligament

Question 10

Blood supply of the foregut

Answer 10

Celiac trunk

Question 11

From where and from what does the esophagus develop

Answer 11

from the foregut tube immediatly caudal to the pharynx

Question 12

Germ cell contributions to the esophagus

Answer 12

Local endoderm: epithelium and glands

Mesenchyme from 4th and 6th pharyngeal arches: skeletal muscle

Local splanchnic mesoderm: smooth muscle

Question 13

Mechanism by which the esophagus forms

Answer 13

occlusion and recanalization which is completed by the 8th week

Question 14

Initiation of stomach development

Answer 14

fusiform dialation of the tubular foregut during the 4th week

Question 15

How does the stomach grow?

Answer 15

ventrodorsally

Question 16

What does dorsal border of the stomach become

Answer 16

greater curvature of the stomach

Question 17

How does the ventral border of the stomach rotate

Answer 17

rotates to face the right

Question 18

How does the dorsal border of the stomach rotate

Answer 18

rotates to face the left

Question 19

How does the crainial end of the stomach bend

Answer 19

to the left and slightly caudally

Question 20

How does the caudal end of the stomach bend

Answer 20

to the right and slightly cranially

Question 21

Where is the stomach (a) suspended from and (b) from what structue is it suspended

Answer 21

from the dorsal abdominal wall by the dorsal mesogastrium

Question 22

How is the greater omentum formed

Answer 22

during stomach rotation, the dorsal mesogastrium moves to the left and then grows as the grater omentum

Question 23

What is duodenal stenosis

Answer 23

incomplete recanalization of the lumen

Question 24

What is duodenal atresia

Answer 24

Failure of the lumen to recanalize

Question 25

When does the hepatic diverticulum invade the septum transversum

Answer 25

Early in the 4th week

Question 26

Cranial bud of the hepatic diverticulum forms what

Answer 26

the liver primordium

Question 27

Caudal bud of the hepatic diverticulum forms what

Answer 27

gallbladder primordium

Question 28

What does the ventral pancreatic bud become

Answer 28

the uncinate process

Question 29

Midgut looping

Step 1: herniation of the midgut

Answer 29

elongation of the midgut forms a ventral U-shaped loop that projects into the proximal part of the umbillical cord

Question 30

When does midgut herniation occur

Answer 30

at the beginning of the sixth week

Question 31

What is attached to the apex of the midgut loop

Answer 31

the vitelline duct

Question 32

Cranial limb of midgut loop forms what?

Answer 32

small intestinal loops

Question 33

Caudal limb of midgut loop forms what?

Answer 33

cecal swelling which is the primordium of the cecum and appendix

Question 34

Midgut looping

Step 2: rotation of midgut loop

Answer 34

while in the umbillical cord, the loop rotates 90 degrees counterclockwise; this brings the crainal limb (small intestine) to the right and the caudal limb (large intestine) to the left

cranial limb elongates and forms intestinal loops

Question 35

Midgut looping

Step 3: Retraction of the intestinal loops

Answer 35

intestines return to the abdomen during the 10th week; small intestine returns first and large intestine undergoes a 180 degree counterclockwise rotation as it returns

Question 36

What is the cloaca

Answer 36

space into which hidgut and allantois (urinary bladder) empty

Question 37

What happens with growth of the urorectal septum

Answer 37

separation of the cloaca into the urogenital sinus and anorectal canal AND separation of cloacal membrane into urogenital membrane and anal membrane

Question 38

What is the urogenital sinus

Answer 38

bladder+urethra

Question 39

What is the anorectal canal

Answer 39

rectum+anal canal