Animal Digestive System ( Note-Taking Guide)

1. Animal Digestive System(Note-Taking Guide) Topic # 3024Ms. Blakeley http://www.glenroseffa.org

2. Digestive System – Objectives • Describe and understand the basic functions of the primary components of the digestive system. • Compare the functions and locations of the digestive organs in man, poultry, horses, cows and swine. • Differentiate between and identify digestive systems of man, horses, swine, poultry and cows.

3. Digestive System • Where large complex molecules are broken down into simpler molecules • Digestive Tract: • Long tube beginning with mouth and ending with the anus • _________________ (Ruminant) • A stomach with more than one compartment • (cows, sheep, deer) • _______________ (Non-ruminant) • A stomach with one compartment • (swine, horses) • ___________ (Poultry) • No true stomach • (chickens, geese)

4. Digestive Systems • _______ & ______ have a simple stomach with an extensive intestinal system • __________ & _________ have a simple stomach with an extensive intestinal system and an enlarged caecum • ____________ have a complex stomach with a simpler intestinal system • ___________ have no teeth and no true stomach with a crop and gizzard to grind food

5. Mouth & Esophagus • Mouth: “prehensile” tool (grasps & mixes food) • Chewing breaks down food • Salivary Glands secrete juices containing enzymes (digest food) • Mucin lubricates the feed for swallowing • Esophagus: muscular tube that connects mouth to stomach • Peristaltic waves send feed down the esophagus, (muscle contractions). • Reverse Peristalsis = blowing chunks • The cardia, located at the end of the esophagus prevents feed in the stomach from coming back into the esophagus. ( non-ruminants only)

6. Simple Stomach • Muscular organ, receives feed • Gastric juices are secreted by the glands in the stomach wall • start when masticated feed enters the stomach • Gastric juices have about 0.2 to 0.5 percent HCl • The wall of the stomach is lined with muscle, this muscle churns and squeezes the feed • This action forces the liquid portion on into the small intestine

8. Ruminant Stomach • Occupies 3/4 of abdominal cavity, mostly on the left side • _________ (paunch): 80% of stomach, lighter food collects here • Microbes digest cellulose • Uses lots of water • _______________ (hardware stomach): 5% of stomach, heavy foreign items are trapped here

9. Ruminant Stomach (cont.) • __________(many plies): 8% of stomach, absorbs water • ______________(true stomach): 7% of stomach, typical enzyme activity • Rumination= regurgitation, re-chewing of food

10. Rumination (regurgitation) • After rumen if full, it lies down to ruminate (chew its cud) • Cattle spend from 5-7 hours ruminating, broken up into 6-8 periods • Regurgitation is the process of forcing the feed back into the mouth for chewing • Done through a series of muscular contractions and pressure in the rumen and reticulum

12. Avian stomach/gizzard • Since chickens have no _____, they swallow food whole and it’s stored in the _______ • Feed in proventriculus are secreted by the glandular stomach and mixed with feed • The feed moves to the _______and is ground • Epithelium breaks the feed into smaller particles, further mixing proventricular digestive juices with the feed in the gizzard • The end of the digestive system is the vent

14. Small & Large Intestines • Small Intestine: long coiled tube connecting __________ to large intestine • rest of the digestion and absorption takes place here • surface covered with villi (surface area) • Large Intestine:_________, colon, rectum • absorbs water (makes feces more solid) • some vitamins & minerals absorbed here • Cecal Fermenters (Horse): similar to rumen