1. Comparative Digestion Systems &Process Modified by Ashlee Gibson

2. The Digestion Process Food is broken down Animals have digestive systems adapted to the foods that they consume Four types of digestive systems –Ruminant(polygstric) –Simple Stomach(monogastric) –Avian –Equine-modified simple stomach

3. Ruminant Digestive System Modified to handle the breakdown of large amounts of fiber

4. Ruminant Digestive System Mouth –no upper incisors, hard palate –molars for grinding coarse vegetation –saliva does not contain enzymes Esophagus –muscular tube connecting the mouth to the stomach

5. Ruminant Digestive Systems The Four Compartmented Stomach Rumen: storage area and fermentation vat Reticulum: nails and wire may be found here-hardware stomach Omasum: eliminates excess water from feed Abomasum: true stomach, gastric juices and enzymes are secreted

6. Ruminant Digestive Systems Stomach (cont.) Regurgitation: first step in rumination –large quantities of roughage are consumed and are chewed just enough to swallow –after swallowing, regurgitation (“cud chewing”) takes place, food is re-chewed

7. Ruminant Digestive System Small Intestine –connects stomach to large intestine –food nutrients absorbed into blood –contains bile and pancreatic juices –pushes food through by muscle contractions

8. Ruminant Digestive System Large Intestine –Contains Cecum, Colon and Rectum Cecum: sac at junction of small intestine and large intestine Colon and rectum: at end of system –not as long as small intestine, but larger in diameter –water and some nutrient absorption occurs here –where residue solidifies before excretion

9. Monogastric Digestive System Characterized by inability to digest roughage efficiently

10. Monogastric Digestive System Mouth –has upper and lower incisors –digestive enzymes secreted which breaks down nutrients Esophagus –connects mouth to stomach

11. Monogastric Digestive System Stomach –secretes Hydrochloric Acid to break down nutrients –enzymes such as pepsin also secreted here –churning action mixes food –small and large intestine function just as in ruminant systems

13. Avian Digestive Systems Characterized by several organs not found in other species that are adapted for grinding hard or encased food

14. Avian Digestive Systems Mouth –no teeth which leads to the saying “scarce as a hen’s teeth!!” –Salivation excretion moistens food Esophagus –has a modification called the “crop” which stores and moistens food –connects mouth and stomach

15. Avian Digestive Systems Stomach –Contains two parts Proventriculus:same as monogastric stomach and provides digestive excretions Gizzard: located after proventriculus, very muscular, used to grind food

16. Avian Digestive Systems Small Intestine –similar functions as in ruminants and monogastric systems Large Intestine –similar functions as in ruminants and monogastric systems –“cloaca”: chamber into which urinary and genital canals open –“ceca”: aids in fiber digestion and absorption

18. Equine Digestive Systems Characterized by non-ruminant animals that consume and digest feeds high in fiber

19. Equine Digestive Systems Mouth –intact top and bottom incisors –molars adapted to chewing fibrous feeds –no digestive enzymes in saliva Esophagus –not well adapted for regurgitation –connects mouth and stomach

20. Equine Digestive System Stomach –similar to monogastric system Small intestine –similar to monogastric and ruminant systems –no gall bladder to store bile –enlarged cecum to aid in fiber breakdown

21. Equine Digestive System Large Intestine –similar to monogastric systems –cecum (at junction of small and lare intestines) and colon take up most of the volume of the equine digestive system

23. Accessory Organs Organs that aid in the digestive process without actually being part of the digestive system

24. Accessory Organs Pancreas –produces and secretes digestive enzymes –produces insulin which regulates carbohydrate metabolism Liver –produces bile-breaks down fatty acids –stores iron, handles fats and carbohydrates in the blood

25. The End!!

26. References Human Biology –http://ultranet.com/~jkimball/Biologypages/G/GITract.html