Download Digestive System

Digestive System
Digestive System
n
n
Large complex molecules broken down into
simpler molecules
Long tube beginning with mouth and ending
with the anus
Digestive Systems
n
n
n
Man & Pig have a simple stomach with an
extensive intestinal system
Ruminants have a complex stomach with a
simpler intestinal system
Horses & Rabbits have a simple stomach with
an extensive intestinal system and an enlarged
cecum
Digestive System
n
n
n
n
n
n
Mouth: “Prehension” tool (grasps food)
Salivary Glands secrete juices containing enzymes
(digest food)
Chewing food breaks down also
Esophagus: muscular tube that connects mouth to
stomach
Peristaltic Movement: sequential contraction of
ringlike muscles
Reverse Peristalsis = blowing chunks
Simple Stomach
n
n
Muscular contractions break down food
Enzymes break down food:
Gastric: proteins
n Liver & Pancreatic: fats
n
Ruminant Stomach
n
n
Stomach occupies 3/4 of abdominal cavity,
mostly on the left side
Rumen (paunch): 80% of stomach, lighter food
collects here
microbes digest cellulose
n lots of water
n
n
Reticulum (hardware stomach): 5% of stomach,
heavy foreign items are trapped here
Ruminant Stomach
n
n
n
Omasum (many plies): 8% of stomach, absorbs
water
Abomasum (true stomach): 8% of stomach,
typical enzyme activity
Rumination: regurgitation, rechewing of food
Digestive System
n
Small Intestine: long coiled tube connecting
stomach to large intestine
rest of the digestion and absorbtion takes place
here
n surface covered with villi (surface area)
n
n
Large Intestine: Cecum, colon, rectum
absorbs water (makes feces more solid)
n some vitamins & minerals absorbed here
n Cecal Fermenters (Horse): similar to rumen
n
Digestive System
n
n
n
Accessory organs:
Pancreas secretes enzymes to break down fat
Liver (largest internal organ) secretes bile, which
digests fats
n
also stores iron