The development of the GIT tract

Question 1

Name the following labels

Answer 1

• A- aorta*
• b- celiac artery*
• c- cranial mesenteric artery*
• d- caudal mesenteric artery*
• e- midgut*
• f- foregut*
• g- hindgut*

Question 2

Name the following labels

what does the stomach do during development

Answer 2

A- becomes the greater momentum

b-becomes the lesser momentum

c-dorsal mesogatrium

d- the developing spleen

e- the developing stomach

f- developing liver

g- ventral mesogatrium

during development, the stomach rotates anti-clockwise, which stretches both the mesogatrium

Question 3

What does the coeliac artery supply?

what does the cranial mesenteric artery supply?

Answer 3

• supplies the stomach, spleen and the pancreas*
• supplies the small intestine, the caecum adn half of the large intestine*

Question 4

What happens to the location of the intestines during development and why?

Answer 4

Happens outside the abdominal cabvity,as there isn’t enough room. This is called physiological herniation. As the abdominal cavoituy increases, the intestines move back in, the distal part returning last

Question 5

What happens to the small intestine during developmental?

what determines which side of the body the caecum lies on?

what side of the body does the ceacum usually lie on?

which species differs from the Normal ?

Answer 5

Tube starts to expand and loops around the cranial mesenteric artery, clockwise rotation. Wraps 270 degrees. The mesentery suspends the intestines from the dorsal body wall. It ends up wrapped around the artery, which is what is called the root of the mesentery.

• ​The number of times it wraps around the artery
• most species it leis on the RHS
• the pig- located on the LHS due to to extra 180 degree rotation

Question 6

What happens during the colon development in the horse?

in the cow?

Answer 6

• It grows faster than the surrounding area. Grows and hits the diaphragm cranially so turns back in on itself. It drags some mesentery and blood vessels with it*
• in the cow the ascending colon spirals in on itself as a spaced saving mechanism, and due to rapid extension,. There is 2 1/2 turn on way in and 2 1/2 turns on the way out/*

Question 7

Answer 7

A- foregut

b- midgut

c-hindgut

d-diaphragm

e-oesophagus

f- liver

g-longitudinal groove

H-amasum

2- rumen

3- reticulum

4- amasum

5- abamasum

Question 8

What happens during the development of the stomach, and the rumen ?

Answer 8

It grows at different rate. The rumen starts to flip backwards so that it doesn’t hit the dorsal wall. It then goes more caudally as a space saving mechanism

Question 9

Name the following labels

Answer 9

A- dorsal lobe of pancreas

b-ventral lobe of pancrea

c-liver

d-pancreatic ducts

e-gall bladder

f- stomach

Question 10

Describe the development of thre caecum in the horse

what is the key difference in the horses caecum?

Answer 10

• It grows and and curls fowards as it starts hitting the ventral wall. As it curls, you can no longer see where the small intestine comes in, as on medial surface.*
• the key difference is that there is a very sepearte entrance and exit point, which means all the ingesta has to pass through the caecum.*

Question 11

What happens with the 3 different excretory systems during the development of the hindgut?

Answer 11

there is a point, where they all share the same vent. With some species, it stays like this, like the Chicken. In most species, during development, a membrane grows which divides the different tracts up. The membrane grows up to the peritoneum.