COMPARATIVE ANATOMY - Ruminant Digestive System

Question 1

Are ruminants foregut or hindgut fermenters?

Answer 1

Foregut fermenters

Question 2

Which side of the abdominal cavity is predominately taken up by the ruminant stomach?

Answer 2

Left side of the abdominal cavity

Question 3

What is the only organ other than the stomach that is located on the left side of the ruminant abdominal cavity?

Answer 3

Spleen

Question 4

What are the four chambers of the ruminant stomach?

Answer 4

Reticulum
Rumen
Omasum
Abomasum

Question 5

Which chambers of the ruminant stomach are known as the fore-stomach?

Answer 5

Reticulum
Rumen
Omasum

Question 6

What is the collective name for the reticulum and the rumen?

Answer 6

Ruminoreticular unit

Question 7

Which structure seperates the reticulum and the rumen?

Answer 7

Ruminoreticular fold

Question 8

What is the reticular groove?

Answer 8

The reticular groove is fleshy lips of smooth mucosa that run from the oesophageal entry and through the reticulum to the reticulo-omasal orifice

Question 9

What is the function of the reticular groove in unweaned animals?

Answer 9

In unweaned animals, suckling stimulates the closure of the reticular groove to form a tube which directs the ingested milk directly to the omasum and into the abomasum, bypassing the ruminoreticular unit. This prevents the fermentation of the milk which is essential for the neonate to gain maximum nutrition from the milk

Question 10

What can be administered to stimulate the closure of the reticular groove to allow veterinary drugs to pass directly into the omasum and abomasum?

Answer 10

Copper sulphate

Question 11

What are the four sacs within the rumen?

Answer 11

Dorsal sac
Ventral sac
Caudodorsal sac
Caudoventral sac

Question 12

Which structures subdivide the rumen into a dorsal and ventral sac?

Answer 12

Ruminal pillars

Question 13

Which structures subdivide the rumen into a caudodorsal and caudoventral sac?

Answer 13

Coronary pillars

Question 14

Where within the dorsal sac does ingesta enter the rumen?

Answer 14

Ingesta enters the dorsal sac of the rumen via the atrium ruminis

Question 15

Where is the opening to the omasum located within the ruminant stomach?

Answer 15

The reticulum opens into the omasum at the reticulo-omasal orifice

Question 16

Where does the omasal canal run within the ruminant stomach?

Answer 16

The omasal canal runs from the reticulo-omasal orifice to the omaso-abomasal orifice

Question 17

What is the function of the omasal canal?

Answer 17

The omasal canal transports ingesta from the reticulum through the omasum and into the abomasum

Question 18

What is the difference in the shape of the omasum in cattle and sheep?

Answer 18

Cattle: rounded omasum
Sheep: bean shaped omasum

Question 19

Which is the only glandular chamber of the ruminant stomach?

Answer 19

Abomasum

Question 20

What is the largest stomach chamber in neonatal ruminants?

Answer 20

Abomasum

Question 21

Which artery supplies the ruminant stomach?

Answer 21

Coeliac artery

Question 22

Which nerve innervates the ruminant stomach?

Answer 22

Vagus nerve

Question 23

Describe the locations of the greater and lesser omentum within the ruminant abdominal cavity

Answer 23

Greater omentum: extends from the greater curvature of the abomasum to the duodenum

Lesser omentum: extends from the lesser curvature of the abomasum to the hilus/porta hepatis of the liver

Question 24

At which side of the abdomen are the ruminant intestines located?

Answer 24

The right side of the abdominal cavity

Question 25

What is the widest part of the ruminant intestine?

Answer 25

Caecum

Question 26

Describe the appearance of the ruminant ascending colon

Answer 26

The ruminant ascending colon forms a sigmoid flexure when it exits the ileocaecocolic junction followed by a double spiral shape

Question 27

How many loops of the ascending colon are usually seen in cattle?

Answer 27

Two ascending colon loops

Question 28

How many loops of the ascending colon are usually seen in sheep?

Answer 28

Three or four ascending colon loops

Question 29

At which side of the abdominal cavity is the liver found in the ruminant?

Answer 29

The right side of the abdominal cavity

Question 30

What are the four liver lobes found in the ruminant?

Answer 30

Left lobe Quadrate lobe Right lobe Caudate lobe

Question 31

What are there three structures which suspend the liver in the ruminant abdominal cavity?

Answer 31

Triangular ligaments Round ligament Lesser omentum

Question 32

Where is the ruminant gallbladder located?

Answer 32

Between the quadrate and right liver lobes

Question 33

What is the difference between the pancreatic duct in large and small ruminants?

Answer 33

In large ruminants, the pancreatic duct empties directly into the duodenum whereas in small ruminants, the pancreatic duct combines with the common/terminal bile duct and empties into the duodenum