Large Animal Abdomen

Question 1

What are the main nerves that innervate the abdominal wall?

Answer 1

• ventral branch of T13
• iliohypogastric nerve (ventral branch of L1)
• ilioinguinal nerve (ventral branch of L2/L3)
• lateral femoral cutaneous nerve (ventral branch of L3/L4)

Question 2

What are the attachments of the greater omentum in the ox?

Answer 2

• greater curvature of abomasum
• reticulum
• mesoduodenum of descending duodenum
• left longitudinal groove of rumen (superficial leaf)
• right longitudinal groove of rumen (deep leaf)

Question 3

What is the supraomental recess?

Answer 3

the region that contains the intestines dorsal to the sling created by the greater omental leaves

Question 4

What are the major features of the Rumen?

Answer 4

• largest compartment
• fills entire left side of abdomen
• papillae varying in size and density

Question 5

What are the grooves and corresponding pillars of the Rumen?

Answer 5

• left and right longitudinal grooves/pillars: divide rumen into dorsal and ventral sacs
• dorsal and ventral coronary grooves/pillars: divide caudal aspect into caudoventral and caudodorsal blind sacs
• right accessory groove/pillar: extends from cranial to caudal groove/pillar
• left accessory groove/pillar: extends dorsally from cranial groove/pillar

Question 6

What is the Intraruminal orifice?

Answer 6

• region bounded by right and left longitudinal pillars, and cranial and caudal pillars
• communication between dorsal and ventral sacs

Question 7

What is the Insula ruminis?

Answer 7

• space between the right accessory pillar and right longitudinal pillar

Question 8

What is the recessus ruminis?

Answer 8

most cranial compartment of the ventral sac of the rumen

- located ventral and caudal to the cranial pillar

Question 9

What is the function of the Rumen?

Answer 9

digestion of complex carbohydrates, and absorption of the resultant VFAs

Question 10

What vessels supply the Rumen?

Answer 10

• right ruminal artery (branch of splenic artery)

- left ruminal artery

Question 11

What innervates the ruminant stomach?

Answer 11

the dorsal vagal trunk

- ventral for abomasum

Question 12

What are the major features of the Reticulum?

Answer 12

• cranial position close to liver and diaphragm
• honey comb-like cells
• reticular groove with left and right lips

Question 13

What is traumatic reticulitis or “hardware disease”?

Answer 13

• when a piece of metal is lodged in the reticulum

- if sharp, it can pierce through the reticulum and diaphragm, and into the pericardium or heart

Question 14

What are the functions of the Reticulum?

Answer 14

• mechanical digestion, filtration of particulate matter, movement, and absorption
• holds course material in, or sends back to rumen

Question 15

What are the main features of the Omasum?

Answer 15

• spherical shape

- parallel folds (laminae) with papillae and interlaminar recesses

Question 16

What are the functions of the Omasum?

Answer 16

• mechanical digestion and absorption

- biphasic contraction to bring ingesta in, expel fluids, and send solids to abomasum

Question 17

What are the main features of the Abomasum?

Answer 17

• glandular stomach
• spiral folds that do not disappear with distention
• lined with glandular mucosa

Question 18

What is the function of the Abomasum?

Answer 18

• chemical digestion via release of enzymes and chemicals from gastric glands

Question 19

What is the Torus pyloricus?`

Answer 19

a round protuberance in the pylorus that augments the pyloric sphincter

Question 20

What vessels supply the lesser curvature of the Abomasum?

Answer 20

right and left gastric arteries

Question 21

What vessels supply the greater curvature of the Abomasum?

Answer 21

right and left gastroepiploic arteries

Question 22

What is the Gastric groove?

Answer 22

• reticular groove + omasal groove + anomasal groove
• allows ingested material to bypass the forestomachs and go directly to abomasum
• unweaned calf drinking milk
• dehydration in adults
• use of ADH or copper sulfate in adults

Question 23

What is the separation of the glandular and non-glandular regions in the horse stomach?

Answer 23

Margo plicatus

Question 24

Describe the course of the ascending colon in the horse

Answer 24

• right ventral colon runs cranially, turns as ventral diaphragmatic flexure, and continues caudally as left ventral colon
• turns as pelvic flexure, and runs cranially as left dorsal colon, turns as dorsal diaphragmatic flexure, and runs caudally as right dorsal colon

Question 25

What are the differences in the small intestine of the ox?

Answer 25

Jejunum: surrounds the spiral loop of the ascending colon - lymph nodes appear as a solitary line running with the intestine Ileum: connected to cecum via ileocecal fold

Question 26

Describe the course of the ascending colon in the ox

Answer 26

- proximal loop (sigmoid shape) - centripetal gyri (spiral inwards) - central flexure - centrifugal gyri (spiral outwards) - distal loop (sigmoid shape)

Question 27

What are the differences in the small intestine in the horse?

Answer 27

Duodenum: duodenocolic fold connects ascending duodenum and descending colon Ileum: no antimesenteric ileal branch - ileocecal fold attaches ileum to cecum - opens to cecum via ileal orifice and papilla

Question 28

Describe the location of the cecum in the horse

Answer 28

- base attached to dorsal body wall - body projects into right ab. wall, and held in place by cecocolic fold - apex extends cranially on ab. wall floor, between left and right ventral ascending colon

Question 29

How many bands are present on the cecum and colon parts? | What are the bands called?

Answer 29

- Taenia coli - cecum: 4 - ventral colon: 4 - pelvic flexure and LDC: 1 - dorsal diaphragmatic flexure and RDC: 3 - transverse and descending colon: 2

Question 30

What vessels supply the ascending colon of the ox?

Answer 30

- colic branch of ileocolic a. supplies proximal loop and centripetal gyri - right colic a. supplies centrifugal gyri and distal loop

Question 31

What vessels supply the ascending colon of the horse?

Answer 31

- colic branch of ileocolic a. supplies ventral colon | - right colic a. supplies dorsal colon

Question 32

What vessels supply the transverse colon in the ox and horse? Descending colon?

Answer 32

transverse: middle colic a. descending: left colic a.

Question 33

Where can the horse get intestinal entrapment?

Answer 33

- epiploic foramen: jejunum and ileum trapped within it | - nephrosplenic ligament: large colon trapped over this ligament which connects spleen and left kidney

Question 34

What are main impaction sites in the horse?

Answer 34

- ventral colon turning as pelvic flexure | - right dorsal colon to transverse colon

Question 35

Which viscera are commonly displaced in the horse?

Answer 35

- apex of cecum | - most of ascending colon, mainly pelvic flexure and left colon