1. Digestive System Chapter #2 Extension

2. Digestive System n Large complex molecules broken down into simpler molecules n Long tube beginning with mouth and ending with the anus

3. Digestive Systems n Man & Pig have a simple stomach with an extensive intestinal system n Ruminants have a complex stomach with a simpler intestinal system n Horses & Rabbits have a simple stomach with an extensive intestinal system and an enlarged cecum

4. Digestive System n Mouth: “Prehension” tool (grasps food) n Salivary Glands secrete juices containing enzymes (digest food) n Chewing food breaks down also n Esophagus: muscular tube that connects mouth to stomach n Peristaltic Movement: sequential contraction of ringlike muscles n Reverse Peristalsis = blowing chunks

5. Simple Stomach n Muscular contractions break down food n Enzymes break down food: –Gastric: proteins –Liver & Pancreatic: fats

7. Ruminant Stomach n Stomach occupies 3/4 of abdominal cavity, mostly on the left side n Rumen (paunch): 80% of stomach, lighter food collects here –microbes digest cellulose –lots of water n Reticulum (hardware stomach): 5% of stomach, heavy foreign items are trapped here

8. Ruminant Stomach n Omasum (many plies): 8% of stomach, absorbs water n Abomasum (true stomach): 8% of stomach, typical enzyme activity n Rumination: regurgitation, rechewing of food

10. Digestive System n Small Intestine: long coiled tube connecting stomach to large intestine –rest of the digestion and absorbtion takes place here –surface covered with villi (surface area) n Large Intestine: Cecum, colon, rectum –absorbs water (makes feces more solid) –some vitamins & minerals absorbed here –Cecal Fermenters (Horse): similar to rumen

11. Digestive System n Accessory organs: n Pancreas secretes enzymes to break down fat n Liver (largest internal organ) secretes bile, which digests fats –also stores iron