Week 13: Ruminant Abdomen Flashcards
What is a ruminant?
Mammals that are able to convert a plant’s cellulose lignin into fatty acids via bacterial fermentation.
Where does fermentation occur in the horse?
In the cecum and ascending colon
The horse is considered a “___-____” fermenter
Hind-gut
Four regions of the ruminant stomach
- Reticulum
- Rumen
- Omasum
- Abomasum
What is the true stomach in the ruminant and why?
- Abomasum
- Glandular equivalent of the monogastric species
Purpose of a large abomasum in a newborn calf
Milk digestion
Orientation and size of the abdominal viscera varies with
Age and pregnancy
The stomach fills what side of the abdomen
Left
The stomach extends where?
- From the diaphragm to the pelvic inlet
- Over the median plane to the right half of the abdominal cavity
The stomach is in contact with what?
- The parietal surface of the left abdominal wall
- Diaphragm
- Floor of the abdomen
The visceral surface of the stomach faces where and is contact with what?
- Right
- Intestines and liver
The rumen is divided into compartments by ____ on the surface that correlate with internal ____ on the luminal surface.
- Grooves
- Pillars
What is the communication between the dorsal and ventral ruminal sac?
Intraruminal ostium
The intraruminal ostium is bound by
- Right and left longitudinal pillars
- Cranial and caudal pillars
The internal aspect of the rumen is covered with
papilla
Papilla in the rumen will vary in size according to
Age, diet, and location in the rumen
Generally, the papilla in the rumen are larger in what direction?
Ventrally
Epithelium of papilla in rumen
Stratified squamous epithelium
Purpose of papilla in rumen
- Protective
- Not ideal for absorption
Another name for traumatic reticulitis
Hardware disease
Hardware disease
Metal collects in the reticulum and can puncture through diaphragm
Reticular groove is located where?
Between the left and right lips of the reticulum
The reticular groove can close to form the ____ ____ in order to take ingesta from where to where?
- Gastric groove
- From esophagus to abomasum
Why would the reticular groove close?
Allows water to bypass rumen during dehydration
Closure of the reticular groove is stimulated by what?
ADH
Sequence of flow if reticular groove is closed
- Cardia
- Reticular groove
- Reticulo-omasal orifice
- Omasal groove
- Omasoabomasal orifice
- Abomasal groove
Sequence of flow with open reticular groove
- Cardia
- Reticular groove
- Reticulum
- Ruminoreticular orifice
- Rumen
- Ruminoreticular orifice
- Reticulum
- Reguritation
The gastric groove is made up of what?
- Reticular groove
- Omasal groove
- Abomasal groove
The cavity of the omasum is occupied by
Laminae
Borders of the paralumbar fossa
- Base: Lumbar transverse processes
- Cranioventral border: Last rib
- Caudoventral border: Ridge formed by the part of the internal abdominal oblique muscle that extends from the tuber coxae to the ventral end of the last rib of the ox
In surgery, access to the rumen and reticulum is gained via
The left paralumbar fossa
The superficial leaf of the greater omentum attaches where?
Left longitudinal groove of the rumen
The deep leaf of the greater omentum attaches where?
Right longitudinal groove of the rumen
Where do the bulk of the intestines reside?
The supraomental recess - a sling formed by the superficial and deep leaves of the greater omentum
The superficial and deep leaves of the greater omentum border what?
The omental bursa
The lesser omentum connects what to what?
The lesser curvature of the abomasum to the hilus of the liver
The supraomental recess is bounded by
- The rumen on the left
- The greater omentum on the right
- Open-ended caudally
Main blood supply to the rumen
The right ruminal artery - a branch of the splenic artery
The right ruminal artery courses where?
In the right accessory groove, through the caudal groove
The right ruminal artery gives off what branches? Where?
Right and left dorsal and ventral coronary arteries within correspondent coronary grooves
The left ruminal artery courses where?
Through the cranial groove from the right to left and extends into the left accessory groove
Main blood supply to the omasum
The left gastric artery, a branch of the celiac artery
Main blood supply to the reticulum
Reticular artery of the left ruminal artery
Main blood supply to the greater curvature of the abomasum
Left and right gastroepiploic arteries
Main blood supply to the lesser curvature of the abomasum
Left and right gastric arteries
Major innervation of the rumen, omasum, and reticulum
The dorsal vagal trunk
Minor innervation of the rumen, omasum, and reticulum
The ventral vagal trunks
Where are the caudal mediastinal lymph nodes located?
Dorsal to the esophagus
Parts of the ruminant duodenum
- Cranial part
- Cranial flexure
- Descending part
- Caudal flexure
- Ascending part
- Duodenojejunal flexure
- Mesoduodenum
The jejunum surrounds what?
The spiral loop of the ascending colon
Parts of the ruminant large intestine
- Cecum
- Ascending colon
- Transverse colon
- Descending colon
- Rectum
Parts of the ascending colon
-Proximal loop
-Spiral colon
+ Centripetal gyri
+ Central flexure
+ Centrifugal gyri
-Distal loop
What supplies the blood of the proximal loop and centripetal portion of ascending colon?
Colic branch of the ileocolic artery
What supplies the blood of the centrifugal portion and distal loop of the ascending colon?
Right colic artery
