lab 16 gastrointestinal physiology Flashcards
how is a rumen fistula made?
an oblong opening is made in the left flank; the muscle and peritoneum are split. the rumen wall is pulled directly through the opening where it is sutured tightly to the skin layer. once completed, the center portion of the rumen wall is cut away, leaving a circular opening for the insertion of the fistula.
is the rumen completely full?
no
what would happen if the rumen were completely full?
mixing could not occur properly;
what is the normal pH of the rumen?
6.8?
what is the significance of the granules in some of the larger protozoa?
they sequester starch and this helps make fermentation slower and more even
what is the sequence of events of a primary contraction?
there is a double reticular contraction; the last contraction contiunes spreading from the reticulum and passes to the omasum. it also passes to the dorsal sac of the rumen and continues into the blind sac of the caudal rumen; a slower wave travels through the ventral sac after this dorsal sac contraction from cranial to caudal and then from caudal to cranial.
how often do primary contractions occur in general?
they occur every 40-60 seconds
how often do primary contractions occur when an animal is eating?
every 40 seconds
how often do primary contractions occur when an animal is ruminating
every 50-60 seconds
how often do primary contractions occur when an animal is resting
every 70 seconds
what is the function of the primary contraction?
to mix the digesta within the rumen and assist with the movement of the fine particles into the omasum
where should you listen to rumen contractions?
in the left paralumbar fossa
what generates the sounds that you hear on listening to rumen contractions?
ingesta rubbing the walls
what sac are you hearing when you listen at the paralumbar fossa?
the dorsal sac
what is the role of secondary contractions?
they assist the animal in eructating rumen gases
what is the sequence of events of a secondary contraction?
the dorsal blind sac travels in a cranial direction toward the cardia or entrance of the esophagus
the the dorsal sac contracts caudal to cranial, then the ventral sac contracts caudal to cranial.
how much gas from eructation travels into the lungs?
60%
how much gas from eructation makes it out the mouth
40%
when do secondary contractions occur?
they usually follow primary contractions
how many contractions should one hear a minute?
2: a primary contraction and a secondary contraction
how does regurgitation occur?
it occurs just before a primary contraction. the reticulum begins contracting and lifts contents to cover the cardia; at the peak of contraction the animal inhales against a closed glottis. the cardia relaxes and the negative pressure draws or sucks rumen contents in; reverse peristalsis occurs
what occurs when the rumen is artificially bloated?
the left side expands first; increases rumen pressure stimulates tensio nreceptors and slows rumen contraction;
where would you find a magnet when giving it to an animal for prevention of hardware disease?
in reticulum or rumen
why does a magnet help reduce the incidence of hardware disease?
prevents objects from piercing the rumen wall
