Ruminant GI- Final Exam Material Flashcards
What is a ruminant?
Ruminants are mammals that are able to convert a plants complex carbohydrates (cellulose lignin) into fatty acids and sugars via bacterial fermentation (symbiotic relationship).
Microbes also synthesize vitamins and recycle nitrogen into protein.
The fermenting microbes THEMSELVES are also a moajor nutritioon source for ruminants
Where does fermentation occur in the horse?
In the cecem and ascending colon, after the small intestine, hence “hind-gut” fermenter
What are the four regions of the ruminant stomach (oral to aboral)?
Rumen
Reticulum
Omasum
Abomasum
What is the true, glandular stomach in the ruminant?
abomasum
How does the orientation and size of the abdominal viscera change with age and pregnancy in ruminants?
In a newborn calf: large abomasum – important for milk digestion rather than fermentation
In the 5 year old cow: the rumen is large and occupies the entire left side of the abdomen; the liver is pushed cranially
In the 6-year old heavily pregnant cow: the uterus displaces the rumen dorsally and the abomasum cranially
Where can you find the rumen?
The entire left side of the abdomen
The rumen is divided into various compartments by ______ on the surface of the rumen that correlate with internal _____ on the luminal surface.
grooves; pillars
Which side of the rumen is the insula ruminis located on? What grooves create this?
right side only
accessory and longitudinal grooves
What are the compartments of the rumen?
Atrium ruminis
Insula ruminis
ventral ruminal sac with ruminal recess
caudoventral and caudodorsal blind sacs
What groove divides the atrium ruminis and the reticulum?
ruminoreticular groove
What is the intraruminal ostium?
caudal to the insula ruminis
communication between the dorsal and ventral ruminal sac (bound by the right and left longitudinal pillars, and cranial and caudal pillars)
What lines the inside of the rumen? How does this lining change with location?
papilla
Papilla are larger ventrally
Describe the contents of the rumen.
The rumen contents will vary from gas dorsally to dense liquid ventrally.
What is hardware disease and where does it occur?
Trumatic reticulitis or “hardware disease” metal will fall here and can penetrate the diaphragm into the heart. Occurs in the reticulum.
How does milk and water bypass the rumen in a calf?
The reticular groove can close to form a tube-like gastric groove to take ingesta from the esophagus to the abomasum.
What stimulates the closure of the reticular groove?
ADH
What is the sequence of flow if the reticular groove is open?
Cardia - reticular groove -
reticulum - ruminoreticular orifice - rumen - ruminoreticular orifice - reticulum - regurgitation
What is the sequence of flow if the reticular groove is closed?
Cardia - reticular groove - reticulo-omasal orifice - omasal groove - omasoabomasal orifice - abomasal groove
What makes up the gastric groove?
reticular groove + omasal groove + abomasal groove
What do we see in the inside of the omasum?
The omasum is occupied by numerous longitudinal folds, or laminae
What structure in the true stomach is unique to the ruminant?
Torus pyloricus located in pyloric region
What are the borders of the paralumbar fossa and why is this important?
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
Access to the rumen and reticulum is gained via the left paralumbar fossa
What are the sites of attachment for the greater omentum in the ruminant? Why does this even matter?
Long longitudinal groove of the rumen (superficial leaf)
Right longitudinal groove of the rumen (deef leaf)
The superficial and deep leaves of the greater omentum form a sling within which the bulk of the intestines reside
Where are the bulk of the ruminant intestines located?
Within the supraomental recess on the right side
The supraomental recess is bound by the rumen on the left and by the greater omentum on the right
What is the main blood supply for the rumen?
Right ruminal artery! This is a branch of the splenic artery.
What is the blood supply for the abomasum?
Same as in the dog.
Greater curvature: left and right gastroepiploic aa.
Lesser curvature: left and right gastric aa.
What is the major source of innervation for the ruminant stomach?
dorsal and ventral vagal trunk (parasympathetic)
Anything special about the duodenum of the ruminant?
Not really.
How does the location of jejunal lymph nodes differ between small and large ruminants?
Ox: found in the
mesojejunum between the jejunum and colon
Goat: Minimal distance between jejunum and spiral colon in small ruminant (last centrifugal loop is in between the lymph nodes and jejunum)
What makes up the ascending colon of the ruminant?
proximal loop + spiral colon + distal loop
What are the components of the spiral colon (oral to aboral)?
Centripetal gyri, central flexure, centrifugal gyri
How is the blood supply to the ascending colon of a ruminant different from the dog?
Colic br. of ileocolic a. supplies the first half of ascending colon: proximal loop, centripetal gyri of the spiral loop
Right colic a. supplies the second half of
ascending colon: centrifugal gyri of spiral loop, distal loop