DIGESTIVE SYSTEM Flashcards
seizing and conveying of feed into the mouth
PREHENSION
principal prehensile structures
lips (beak in birds)
teeth
tongue
prehensile structures: cattle
tongue and lower incisors.
prehensile structures: horses and sheep
lips and teeth
possess a complete set of incisors and molars
pig and horse
chewing;
mechanical breakdown of feed into finer particles;
allows the feed to be well mixed with saliva to facilitate swallowing
mastication
mixing of feed with saliva;
greatest during feeding, mastication, remastication in ruminants.
insalivation
lubricates the feed bolus, adds small amounts of amylase, and because of its alkalinity and large volume, buffers the pH in the rumen
saliva
mechanical breakdown of feed and the consequent chemical changes brought about by digestive juices, bacteria, and protozoa;
breakdown of feed particles into suitable products for absorption
digestion
a complex protein produced in living cells that causes changes in other substances within the body without being changes itself (organic catalyst)
enzymes
enzyme of saliva
salivary amylase/ptyalin
enzymes of rumen
microbial cellulose
microbial amylase
microbial proteases
microbial urease
enzyme of stomach, abomasum, and proventriculus
pepsin
enzymes of pancreas (enzymes are secreted into the duodenum)
trypsin
chymotrypsin
carboxypeptidase
starch to maltose; begins the initial digestion of sugars and starch
salivary amylase/ptyalin
cellulose to volatile fatty acids
microbial cellulose
starch to volatile fatty acids and lactic acid
microbial amylase
protein to amino acids and NH3
microbial proteases
urea to CO2 and NH3
microbial urease
protein to polypeptides
pepsin
protein to peptides and amino acids
trypsin
chymotrypsin
carboxypeptidase
transfer of substance from gastro intestinal tract (GIT) to the circulatory (blood or lymph) system;
occurs when nutrients are broken down to very small molecules to their basic units with the action of enzymes;
occurs primarily in the small and large intestine.
ABSORPTION
PARTS OF THE DIGESTIVE SYSTEM
- mouth and buccal cavity
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- accessory glands
3 divisions of small intestine
- duodenum
- jejunum
- ileum
3 sections of large intestine
- cecum
- colon
- rectum
what are the accessory glands?
pancreas
liver
for prehension, mastication and insalivation;
used in bolus formation in ruminants;
has 3 accessory glands
- mouth and buccal cavity
3 accessory glands of mouth and buccal cavity
- tongue
- teeth
- salivary glands
grasping of food
- tongue
mastication of food
- teeth
produvced saliva w/c contains water to moisten food;
mucin to lubricate food for easy swallowing; bicarbonates salts to buffer(regulate pH);
salivary amylase to start carbohydrate digestion
- salivary glands
common passage for air and feed
pharynx
the inspired air crosses to the pharynx to enter the …
larynx
the feed crosses the pharynx to enter the ….
esophagus
muscular tube which connects the stomach to the mouth;
allows passage of food from mouth to stomach.
esophagus
muscular organ w/c is the site for feed storage, grinding, and mixing of feed, absorption, enzymatic action and microbial fermantation.
stomach
3 majoir functions of stomach:
- storage of ingested feed,
- mechanical breakdown,
- production of HCL, enzymes and mucus
an active site of digestion that receives secretions from the pancreas, liver and intestinal walls.
duodenum
middle section of small intestine that is involved in nutrient absorption.
jejunum
last section of small intestine;
also involved in nutrient absorption
ileum
continue protein hydrolysis
proteolytic enzymes
converts starch to maltose
pancreatic amylase
reduce dipeptides to single amino acids
peptidase enzymes
produced by the liver, stored and secreted by the gall bladder(not present in the horse);
aids digestion in the small intestine by emulsifying fat particles
bile
enhance digestion in small intestine (4)
proteolytic enzymes
pancreatic amylase
peptidase enzymes
bile
first section of large intestine w/c is relatively large in the horse and rabbit;
when well developed as in the horse contains many bacterial w/c produced enzymes that digest fiber
cecum
middle section of large intestine w/c is involved in reabsorption of water;
length is related to amount of water reabsorption
e.i., very long in the desert rat
colon
last section of large intestine
rectum
produces digestive enzyme needed in the digestive processes that take place in small intestine
pancreas
secretes bile needed for emulsification of fat in the small intestine
liver
types of animals based on their stomach structure
- monogastric
- modified simple stomach
- compound stomach/ ruminants
simple stomach. one compartment;
includes swine and horses
- monogastric
digestive pathway for feeds in monogastrics:
mouth - esophagus - simple stomach - small intestine (duodenum, jejunum, ileum) - large intestine, (and cecum) - rectum - anus
can be found in poultry species w/ the following modifications: gizzaed, crop, proventriculus
modified simple stomach
avian GI tract (4)
mouth
esophagus
proventriculus
gizzard/ventriculus
avian GI tract
- does not contain teeth, beak used to collect particles of feed and to beak some large particles into smaller pieces;
tongue and salivary glands are present and saliva contain salivary amylase
mouth
avian GI tract
- include an enlarged area called crop
esophagus
avian GI tract
- corresponds to the true stomach;
site of HCI and pepsin production in bird
proventriculus
avian GI tract
- muscular area w/c contains grot; the involuntary muscular contraction aid in the mechanical breakdown of food.
gizzard/ventriculus
avian GI tract
- temporay storage and moistening of food, as aplace of salivary amylase to work, and as microbial fermantation in some species
crop
digestive pathway in poultry:
mouth - esophagus - crop - proventriculus (stomach) - gizzard - small intestine - large intestine (and ceca) - cloaca - vent
general term for those possesing a single stomach compartment (as well as the modified stomach)
NON-RUMINANT
with 4 compartments (in mature);
able to rapidly ingest and store large quantities of fibrous feeds in their rumen;
able to conver feeds that are ingestible by humans and other monogastrics into useful nutrients and products;
able to utilize fibrous feeds, non-protein N, and they can produce all of the essential amino acids and B-complex vitamins
- compound stomach/ ruminants
exmaples of compound stomach/ ruminants animals
cattle
carabao
sheep
goat
digestive pathway in ruminants
mouth - esophagus - reticulo - rumen - (process of regurgitation, rechewing, reinsalivation, and reswallowing) - reticulo - rumen - omasum - abomasum - small intestine - large intestine (and cecum) - rectum - anus
the formation of “balls” of feed out of masticated feed particles.
bolus formation
4 compartments in compound stomach/ ruminants
- rumen
- reticulum
- omasum
- abomasum
main site of microbial fermantation of feeds;
largest of the four compartments;
left side; covered by projections called PAPILLAE
muscular walls secrete no enzymes
- rumen
regulates the passage of feed from the ruman to the succeeding compartments;
aids regurgitation of feed back to the mouth; also site of microbial fermentation
- reticulum
round muscular organ w/c contains many muscular laminae (sometimes calles manyplies);
further grinds and reduces the feed into finer particles before the feed enters the abomasum
- omasum
true stomach of the ruminants
- abomasum
projections that is required for absortion of nutrients
PAPILLAE
3 major benefits of microbial fermentation in ruminants:
- coversion of cellulose from vegetative materials to VFA as sources of energy
- production of microbial protein from feed proteins and non-protein N sources that provide the essential amino acids
- synthesis of Vitamin K and the B-Vitamins
2 functions of reticulum
- to move the food into the rumen or omasum
2. collection of dense particles of food and in regurgitation of ingesta during rumination.
process of movement of ingesta back up the esophagus to the mouth for additional mechanical breakdown
rumination/ “chewing thw cud”
additional unique features of ruminants
esophageal groove
rumination
eructation
begins at the base of the esophagus and when stimulated by sucking forms a tube w/c empties into the abomasums;
function: direct milk obtained from sucking to escape microbial digestions in the rumen
esophageal groove
belching of gas;
allows for removal of large volumes of gas produced in the rumen;
contractions of the upper part of the rumen force the gas up the esophagus and from there the gas penetrates into the trachea and lungs
eructation
