Digestive Tract

Question 1

During the 4th week what happens with the folding of the embryo

Answer 1

Pinching off of the yolk sac
Which creates the primitive gut tube

Question 2

After folding how is the yolk sac connected to the gut tube

Answer 2

Via the yolk stalk

Question 3

How is the gut initially closed off

Answer 3

By the oropharyngeal membrane cranially
Cloacal membrane caudally

Question 4

What is the stomedeum

Answer 4

Primitive oral cavity

Question 5

What is the proctodeum

Answer 5

Anal pit

Question 6

What is the endoderm responsible for

Answer 6

Epithelial lining of the GI tract

Question 7

What is the mesoderm responsible for

What part of the mesoderm

Answer 7

Splanchnic mesoderm: Smooth muscle of GI tract

Question 8

What is the ectoderm

Answer 8

Epithelial lining of the Stomodeum and Proctodeum

Question 9

Where are the different peritoneum

Answer 9

Parietal peritoneum is the parietal layer of the lateral plate mesoderm
Visceral peritoneum is the visceral splanchnic lateral plate of mesoderm
Intraperitoneal is the gut tube’s empty space
Retroperitoneal is behind

Question 10

What is the Mesentery

What does it do

Answer 10

It is a double layer of peritoneum (lines the abdominal cavity and covers organs)
Anchors organs to body wall
Conveys vessels and nerves to organs

Question 11

What is the Dorsal Mesentery

Answer 11

Attaches caudal foregut, midgut and hindgut to dorsal body wall

Question 12

What is the ventral mesentery

Answer 12

Attaches caudal foregut to ventral body wall

Question 13

What are the three supplies of blood off the arota to the GI tracts

Answer 13

Foregut- Celiac Trunk
Superior Mesenteric Artery- Midgut
Inferior Mesenteric Artery- Hindgut

Question 14

What is included in the foregut

Answer 14

Esophagus
Liver
Stomach
Duodenum
Gallbladder

Question 15

What is Midgut

Answer 15

Large and Small Intenstine

Question 16

What is Hindgut

Answer 16

Descending colon and rectum

Question 17

What are the structures of the foregut derivatives

Answer 17

Primordial Pharynx and Derivatives
Esophagus
Lower Respiratory System
Stomach
Liver and Biliary Apparatus (hepatic ducts, gallbladder, & bile duct)
Duodenum (proximal to bile duct)
Pancreas

Question 18

What are the midgut derivatives

Answer 18

Duodenum (distal to bile duct)
Small Intestine (Jejunum and Ileum)
Large Intenstine ( Cecum, appendix, ascending colong, proximal 2/3 of transverse colon)

Question 19

What are the Hindgut Derivatives

Answer 19

Large Intestine (Distal 1/3 of transverse colon. descending colon, and sigmoid colon)
Cloaca Derivatives (Rectum superior anal canal and portion of bladder and urethra)

Question 20

What is the Ventral Mesentery attaches to and what develops in it

Answer 20

Attaches the caudal foregut to the ventral body wall
Liver develops within mesentery

Question 21

Where does the dorsal mesentery attach

Answer 21

Attaches caudal foregut midgut and hindgut to dorsal body wall
Carries blood supply from abdominal aorta

Question 22

What does the mesentery look like

Where does it anchor

Answer 22

It is a fan shaped double layer fold
Anchors the jejunum and ileum to the posterior abdominal wall

Question 23

How does the stomach form

What grows faster

Answer 23

It enlarges and rotates 90 degrees clockwise around longitudial axis
THe posterior stomach grows faster than the anterior stomach which has a greater and lesser curvatures of the stomach

Question 24

How does the caudal and cranial parts of the stomach move

Answer 24

Caudal part moves up and to the right
Cranial part moves down and to the left

Question 25

What happens to the dorsal and ventral mesentery has it is pulled

Answer 25

Dorsal mesentery pulled to the left Creates the omental bursa (lesser sac) Ventral mesentery pulled to the right

Question 26

What does the dorsal mesentery envelop and what does it create

Answer 26

Envelopes spleen pulled to the left enlarges dramatically creates omental bursa

Question 27

What is anterior to the mesenteries

Answer 27

Greater sac

Question 28

What does the dorsal mesentery eventually become

Answer 28

It elongates dramatically forming a double layered sac fusing together with 4 layers of peretirum creating the greater omentum Fushes with mesentery of transverse colong

Question 29

Do the lesser omentum and the omenta bursa conenct

Answer 29

Yes they do

Question 30

What does the greater omentum look like

Answer 30

It is the adipose tissue and blood vessels connects to the interior border of the stomach and attaches to the transverse colong

Question 31

How does the formation of lesser omentum form | What mesentery

Answer 31

The ventral mesentery extends from lesser curvature of stomach and duodenum of liver and ventral abdominal wall The dorsal portion (from stomach and duodenum to liver) gives rise to the lesser omentum

Question 32

What are the two parts of the lesser omentum

Answer 32

Hepatoduodenal ligament - liver to duodenum thicker has structures in it Hepatogastric ligament - liver to stomach lesser curvature it is a thinner portion

Question 33

How does the duodenum develop

Answer 33

5-6 weeks Develops from the distal foregut and proximal midgut Grows rapidly and forms a C-shaped loop The rotation of stomach rotates the duodenal loop to the right and and becomes retroperitoneal

Question 34

What happens with the duodenum lumen

Answer 34

In the 5-6 week the Normal canalization proliferation of epithelial cells temporaily obilterates the lumen of the dudoenum Vaculoation Degeneration of epithelial cells starts to open up aggain By 9 week the Normal Lumen the duodenum is recanalized back to having a lumen

Question 35

What is Congenital Duodenal Artesia | Where does it usually occur

Answer 35

Pretty rate no recanalization of duodenum occurs; complete occlusion Usually occurs at the hepatopancreatic ampulla which is the bile duct and pancreatic duct that open in the duodenum also where the foregut transtions to the midgut

Question 36

What are the symptoms of the congenital duodenal artesia

Answer 36

Bilious vomiting shortly after birth Distention of epigastrium Polyhydramnios may occur (extra amnonic fluid)

Question 37

What is the diagnosis and the treatment of the cogenital duodenal atresia

Answer 37

Double bubble sign Treatment Duodenoduodneostomy