Ruminant GI Tract

Question 1

Approximately how much space in the abdominal cavity does the rumen and reticulum take up in a cow?

Answer 1

Rumen: 80%
Reticulum: 5%

Question 2

What is the difference between a concentrate selector and a grass-roughage eater?

Answer 2

Concentrate selectors eat faster growing plants that are easier to digest because they have more frequent and faster rumen contractions.
Grass-roughage eaters eat tougher foods that take longer to digest

Question 3

What is the function of the esophageal groove?

Answer 3

It allows liquid to bypass the rumen and go straight into the reticulum. This is important in neonates who drink milk and adults that are dehydrated

Question 4

What is the insula ruminis located between?

Answer 4

The longitudinal fold

Question 5

What part of the rumen does a bolus of food first go into from the esophagus?

Answer 5

Atrium ruminis

Question 6

List all the sacs within the cow rumen

Answer 6

Cranial sac
Dorsal sac
Ventral sac
Caudodorsal blind sac
Caudoventral blind sac

Question 7

Which pillars (folds) separate the caudodorsal and caudoventral blind sacs?

Answer 7

Dorsal and ventral coronary pillars respectively. The caudal fold runs between the sacs

Question 8

Which sac is greatly reduced in sheep?

Answer 8

Caudodorsal blind sac

Question 9

What is the structure that divides the cranial sac of the rumen and the reticulum called?

Answer 9

Ruminoreticular groove

Question 10

Which structures are located on the left and right side of the cow?

Answer 10

Rumen - left
Reticulum - left
Omasum - right
Abomasum - mostly right/ventral midline

Question 11

What type of epithelium lines the ruminant GI tract?

Answer 11

Stratified squamous epithelium

Question 12

What is the function of papillae in the rumen?

Answer 12

Greater surface area for efficient digestion

Question 13

What can happen in the reticulum if the cow eats wire or nails?

Answer 13

The foreign objects can become trapped within the deep pockets that line the reticulum and contractions can cause perforations that lead to TRP (traumatic reticular peritonitis)

Question 14

How much abdominal volume does the omasum take up in roughage eaters? What about concentrate selectors?

Answer 14

Roughage eaters - 8%
Concentrate selectors - 4%

Question 15

Where do the folds within the omasum originate?

Answer 15

From the greater curvature

Question 16

What is the structure called that connects the reticulum and the omasum?

Answer 16

Reticulo-omasal orifice

Question 17

What does the omasal canal connect to?

Answer 17

Omasoabomasal orifice

Question 18

What is the abomasum?

Answer 18

The glandular stomach (true stomach) that secretes digestive enzymes

Question 19

What is the large structure in the pylorus called (right before it becomes the duodenum)?

Answer 19

Torus pyloricus

Question 20

What happens to the stomach contents when it enters to omasum?

Answer 20

Liquid is extracted and material becomes very dry

Question 21

What issue can arise with dry material in the omasum?

Answer 21

An omasum impaction. Especially when it is cold, rough feed like straw can become stuck and cause an impaction that spreads into the rumen. not good

Question 22

What structures does the abomasum poke out between on the left side?

Answer 22

Reticulum and ventral sac of rumen

Question 23

What is the origin and insertion of the lesser omentum?

Answer 23

Origin: lesser curvature of abomasum
Insertion: Liver

Question 24

Which side of the cow does the duodenum go up?

Answer 24

The right side, then turns and goes caudally

Question 25

How is the spleen positioned in the cow abdomen?

Answer 25

It's on the left dorsal side of the rumen NOT within the greater omentum. The dorsal part of the spleen is also under the retroperitoneal adhesion and attaches to abdominal wall

Question 26

Which arteries branch off the celiac artery?

Answer 26

Splenic Left gastric Hepatic

Question 27

What does the right rumenal artery branch from?

Answer 27

Splenic a.

Question 28

What does the left rumenal artery branch from?

Answer 28

Splenic a.

Question 29

What does the reticular artery branch from?

Answer 29

Left rumenal a.

Question 30

What does the left gastric artery branch from and then branch into?

Answer 30

From: Celiac a. To: left gastroepiploic a.

Question 31

Which grooves does the right rumenal artery run through?

Answer 31

Runs through the right longitudinal groove to the caudal groove

Question 32

Which groove does the reticular artery run through?

Answer 32

The ruminoreticular groove

Question 33

Which artery supplies the esophagus?

Answer 33

Reticular artery

Question 34

What does the gastroduodenal a. branch from and branch into?

Answer 34

From: hepatic To: right gastroepiploic

Question 35

What does the right gastric artery branch from?

Answer 35

Hepatic a.

Question 36

Which groove does the left rumenal artery run through?

Answer 36

Cranial groove and left longitudinal groove

Question 37

Which two nerve branches supply the ruminant GI tract?

Answer 37

Dorsal vagus Ventral vagus

Question 38

Which structures does the dorsal vagus innervate?

Answer 38

Rumen, omasum, and abomasum

Question 39

Which structures does the ventral vagus innervate?

Answer 39

Reticulum, omasum, and abomasum

Question 40

What issue can TRP (traumatic reticuloperitonitis) cause?

Answer 40

Vagal indigestion - Extensive inflammation can disrupt the ventral vagus nerve and cause a lack of function

Question 41

What does the descending duodenum lie within?

Answer 41

The greater omentum and then fuses with mesoduodenum

Question 42

Which omentum covers the omasum?

Answer 42

Lesser omentum

Question 43

Which sacs of the rumen lie within the omental bursa?

Answer 43

Ventral sac and ventral blind sac

Question 44

What is the omental bursa?

Answer 44

The space between the superficial and deep layers of the greater omentum

Question 45

Which structure takes up most of the abdominal cavity in neonates?

Answer 45

Abomasum - No need for rumen when still on milk

Question 46

What does the superficial layer of the greater omentum come from and attach to?

Answer 46

Comes from the left longitudinal groove, attaches on the greater curvature of the abomasum, and then inserts on the mesoduodenum

Question 47

What does the deep layer of the greater omentum come from and attach to?

Answer 47

Comes from the right longitudinal groove and inserts on the mesoduodenum

Question 48

What lies within the supraomental recess?

Answer 48

Intestines

Question 49

What is the mesentery called that the jejunum is attached to?

Answer 49

Great mesentery

Question 50

How many rotations are there in the cow ascending colon?

Answer 50

2

Question 51

What is the mesentery of the ascending colon fused to?

Answer 51

Left surface of great mesentery

Question 52

What are the two sections of the ascending colon?

Answer 52

Centripetal Centrifugal

Question 53

Which part of the ascending colon runs more inside?

Answer 53

Centripetal

Question 54

Which part of the ascending colon runs closest to the outside (nearer to the jejunum)?

Answer 54

Centrifugal

Question 55

What is the flexure of the ascending colon called that comes right after the cecum and before the centripetal colon?

Answer 55

Sigmoidal flexure (S-shaped)

Question 56

Where is the descending colon located?

Answer 56

On the right face of the dorsal sac of rumen

Question 57

How can a surgeon get through the greater omentum when doing abdominal surgery?

Answer 57

The edge of the greater omentum can be moved cranially for easy access to intestines within the supraomental recess to avoid cutting through it