Chapter 4 Study Questions Flashcards
Define digestion
the preparation of food for absorption
What are the 3 major methods (mechanisms) of digestion?
physical/mechanical, chemical & enzymatic
Why do different animals use very different kinds of feeds?
the digestive system of the animal determines what it can eat. the more complicated the feed, the more complicated the digestive system
what are the two stomach types in livestock?
monogastrics & ruminants (more than one stomach compartment)
what is the subcategory of stomach type?
cecal fermenters = hind gut fermenters
what is prehension?
seizing & conveying of food to the mouth
what is mastication?
chewing
explain the function of chewing of herbivores
they chew thoroughly to allow bacterial enzymes to have access to cellulose by increasing feed surface area
what is salivation?
secretion & mixing of saliva with food
what dictates the amount of saliva that is produced by the various species?
species & diet
how much saliva is produced by carnivores, omnivores and herbivores?
carnivores = smallest, 200 ml/day omnivore = intermediate, 1500 ml/day herbivores = most, horse - 40 L/day, cow - 120+L/day
what are the components of saliva?
water, electrolytes, proteins (lysozymes, salivary amylast & lipase)
8 functions of saliva
lubrication, solvent, washing, disinfectant, buffer, nutrients, antifrothing, excretory
what is deglutition?
swallowing
what is the role of the stomach in digestion?
stores food & performs mechanical & chemical digestion
what are the 3 portions of the small intestine & what are the functions of each?
Duodenum - main site of food breakdown in the sm. intestine
Jejunum - absorption of the end products of digestion
ileum - forms the connection to the large intestine, some absorption here
what does bile do?
assists in digestion & absorption of fats by a detergent action that helps emulsify fats by forming a complex with fatty acids
what does pancreatic juice do?
contains important digestive enzymes
what are the functions of the pancreatic digestive enzymes?
trypsin, chymotrypsin, carboxypeptidase & aminopeptidase = digest proteins
intestinal lipase = breaks fats into fatty acids & glycerol
amylase = digest starch
function of large intestine.
water, electrolytes, vitamins, minerals & volatile fatty acids are absorbed here
what do bacteria do in the gut of a monogastric herbivore?
They help do what the rumen does but not as well. Functions in the digestion of cellulose & in the microbial production of b-complex vitamins
why do rabbits practice coprophagy (cecotropy)?
they adapted to make use of the unused microbial proteins by eating the contents of the cecum directly from the anus and digesting it
how does an animal defecate?
the defecation reflex is stimulated by the pressure of feces in the rectum —> the reflex is assisted by the parasympathetic nervous signal that intensify the peristaltic waves of the large intestine —> many animals use the valsalva maneuver (breathing deeply, closing the glottis & flexing the abdominal muscles) to put pressure on the fecal contents to expel them
what are the components of urine?
Nitrogen compounds (urea & uric acid), sulfurous metabolites, minerals (Cl, K, P, Na) & water
what is the major anatomical difference in ruminants & nonruminants?
the complex stomach of the ruminants
describe the anatomy of the ruminant tract
4 compartments: rumen, reticulum, omasum, abomasum
what are the common names of the 4 ruminant stomachs?
rumen = paunch reticulum = honeycomb, hardware stomach omasum = manypiles, Stockman's Bible abomasum = true stomach
what is the relative volume of each compartment in the ruminant “stomach”?
rumen - 80%
reticulum - 5%
omasum - 7 to 8%
abomasum - 8 to 9%
what is the esophageal groove & what does it do?
it is a muscular groove that can contract & form a tube that acts as a bypass of the rumen & empties into the abomasum
what is the function of the rumen?
the rumen acts as a site of anaerobic bacterial fermentation