Lecture 24

Question 1

Describe the position of the rumen:

Answer 1

Located left and dorsally

Question 2

What part of the rumen remains retroperitonial?

Answer 2

the dorsal part

Question 3

Name the following structures:

Answer 3

1. Liver
2. Rumen
3. Abomasum
4. Omasum

Question 4

Name the following structures of the stomach:

Answer 4

1. dorsal sac of rumen
2. reticulum
3. omasum
4. ventral sac of the rumen

Question 5

Briefly compare the mesentry of the conplex stomach to that of the simple stomach:

Answer 5

The omental bursa originates from both sides of the rumen, (whereas it only originates from one side in the cat and the dog), it then passes up past the body wall to the duodenum and suspends things up there. Within that recess is where the intestines sit. The omental bursa contains some organs, particularly the ventral sac of the rumen, but also the omasum and the abomasum.

Question 6

Briefly describe the appearance of the rumen and relate this to function:

Answer 6

The rumen is involved in microbial fermentation. Short chain fatty acids are produceed here the papillae need to be able to reabsorb them. Has a carpet like appearance

Question 7

Describe the appearance of the reticulum:

Answer 7

Hexagonal shape strucutre, contain papillae in them. Useful for stopping stick and peices of metal

Question 8

Briefly describe the appearance and the function of the omasum:

Answer 8

Comprises of a mucosal surface of cornified internal leaves. Fluid moves inbetween the leaves on the first contraction and on the second contraction fluid is squeezed out of it.

Question 9

Briefly describe the structure of the abomasum:

Answer 9

Has a mucosal surface that contains Rugae within it. It is a typical glandular stomach with no cardia.

Question 10

Describe the contraction sequence involved in the rumen:

Answer 10

1. Contraction begin in the reticulum tipping material into the atria and to the dorsal sac of the rumen
2. Dorsal sac of the rumen then contracts pushing material into the ventral sac of the rumen
3. Ventral sac then contracts and spreads it everywhere else, this contraction sequence keeps proceeding

Question 11

What is the function of the rumeno-reticular groove and what activates it?

Answer 11

It is activated by the suckling action, bypasses the rumn and reticulum so that the milk enters the omasum directly