lecture 1

Question 1

What does the endoderm contribute to the GI tract?

Answer 1

Epithelial lining of the GI tract

Question 2

What does the mesoderm contribute to the GI tract?

Answer 2

Smooth muscle and connective tissue of the GI tract

Question 3

What does the ectoderm contribute tot he GI tract?

Answer 3

Enteric Nervous system

Question 4

What is the arterial supply of the foregut?

Answer 4

Celiac trunk

Question 5

What supplies the midgut?

Answer 5

SMA

Question 6

What supplies the hindgut?

Answer 6

IMA

Question 7

What are the deriviatives of the forgut?

Answer 7

Esophagus
Respiratory tract
Stomach
Duodenum (superior part)
Liver
Gallbladder
Pancreas
Spleen

Question 8

What are the derivatives of the midgut?

Answer 8

Duodenum (descending-> ascending)
Jejunum
Ileum
Cecum
Appendix
Ascending colon
Hepatic flexure
Proximal 2/3rds of transverse colon

Question 9

What are the derivatives of the hindgut?

Answer 9

Distal 1/3rd of  transverse colon
Descending colon
Sigmoid colon
Rectum
Upper anal canal
Urogenital sinus

Question 10

What are important considerations for the devleopment of the midgut

Answer 10

o Recanalization – A process by which a hollow tube becomes covered with villi which increases the surface area of the tube. This occurs throughout the development of the GI tract and is completed by the 9th week of development
o Transverse mesocolon fuses with posterior wall of greater omentum but maintains its mobility
Mesentery proper holds the small intestine

Question 11

What are clinical correlations for the development of the digestive system?

Answer 11

persistence of the vitelline duct causes:
1) Meckels diverticulum - remnant of the vitelline duct and cn result in ulcers/bleeding

2) cysts/fistulas

Question 12

What are the downstream effects of stomach rotation?

Answer 12

§ Creation of the omental bursa
§ Moves spleen into final position
§ Allows formation of greater omentum from the dorsal
mesogastrium
§ Allows duodenum to assume the C-shape
§ Allows fusion of ventral and dorsal pancreatic buds
Pushes proximal ½ of the duodenum retroperionteally

Question 13

Dorsal mesentary is derived from?

Answer 13

visceral mesoderm layers

Question 14

ventral mesentary is derived from

Answer 14

septum transversum

Question 15

What is the embryological precursor to the central tendon of the disphragm?

Answer 15

septum transversum

Question 16

Examples of dorsal mesentary?

Answer 16

Dorsal mesogastrium
dorsal mesoduodenum
mesentary proper
dorsal mesocolon

Question 17

Examples of ventral mesentary

Answer 17

lesser omentum and falciform ligament

Question 18

How is the greater omentum formed?

Answer 18

the stomach rotates and the dorsal mesogastrium hangs inferiorly forming a 4 layered structure

Question 19

What does the spleen originate from? intra vs retro?

Answer 19

Spleen primordium. remains intraperitoneal

Question 20

How is the pancreas formed?

Answer 20

Dorsal and ventral bud fuse during stomach rotation

Question 21

What are the parts of the pancreas?

Answer 21

Uncinate process, head, neck, body, and tail

Question 22

Cephalic limb of the primary intestinal loop becomes what?

Answer 22

small intestines mostly

Question 23

Cephalic limb of the primary intestinal loop becomes what?

Answer 23

large intestines mostly

Question 24

What process coils the small intestines? what are the details?

Answer 24

90 degrees counterclockwise and then 180 degree counterclockwise rotation of the intestines in an out and back pattern. This is midgut rotation!

Question 25

What tissues are invovled with the derivation of the anal canal

Answer 25

superior 2/3rd is endoderm inferior 1/3rd is ectoderm