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comparative anatomy digestive system.pptx
- 1. Comparative anatomy ( Chordates) Digestivesystem 1 Human 2Ruminant 3-Avian 4-Horse 5-Fish
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- 3. Introduction • Three (3)basic types of digestive systems according to their stomachs : ►Monogastric – simple stomach. ►Ruminant (cranial fermentor) – multi-compartmented stomachs. ►Hind gut (caudal) fermentor – simple stomach, but very large and complex large intestine
- 4. Types of DigestiveSystems Cats Chickens Pigs Dogs Turkeys Monogastrics Ruminants Hind Gut Fermentors Beef Cattle Dairy Cattle Deer Sheep Goats Horses Rabbits Ostrich
- 5. Types of DigestiveSystems • Are divided into three groups based on their food sources 1. Herbivores are animals that eat plants exclusively 2. Carnivores are animals that eat other animals 3. Omnivores are animals that eat both plants and other animals 5
- 6. Carnivore • Eat primarily otheranimals. Herbivore • Eat primarily plant materials. omnivore • Eat combination of plant and animal material.
- 7. Introduction • The digestivesystem is used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body.
- 8. Main Functions ofDigestive Tract • The major activities of GI tract • 1-Ingestion: taking in food 2.Motility • Propel ingested food from mouth toward rectum 3.Secretion of juices e.g. saliva • Aid in digestion and absorption 4.Digestion • Food broken down into absorbable molecules 5.Absorption • Nutrients, electrolytes, and water are absorbed or transported from lumen of GIT to blood stream 6.. Egestion(Elimination) : removing any leftover wastes
- 10. Digestion • Types – Mechanical(physical) • Chew • Tear • Grind • Mash • Mix – Chemical • Enzymatic reactions to improve digestion of – Carbohydrates – Proteins – Lipids
- 11. Anatomy of theDigestive Tract GIT consists of; – Oral cavity or mouth – Pharynx – Esophagus – Stomach – Small intestine – Large intestine – Rectum – Anus
- 12. Mouth or oralcavity • Ingestion - bringing food into the body – tongue - taste buds detect chemical composition of food • Mastication - chewing (physical digestion) – teeth and tongue • Chemical digestion - saliva – moistens food – amylase - breaks down starch – lysozyme - antibacterial agent
- 13. Esophagus • Muscular tubeconnecting the pharynx to the stomach. • Functions include: 1.Secretes mucus 2.Moves food from the throat to the stomach using muscle movement called peristalsis Cardiac Sphincter – connects esophagus and stomach • If acid from the stomach gets in here that’s heartburn.
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- 15. Stomach • Muscular sac-likeorgan • Chemical and physical digestion – forms chyme • goblet cells – mucus – forms a protective barrier against the high acidity of the stomach content. – parietal cells – HCl – kills bacteria, denatures proteins • chief cells - pepsinogen – pepsinogen activated by HCl pepsin – pepsin breaks down proteins
- 16. Small intestine Functions Digestion Digest carbohydrates: amylase from pancreas Digest proteins : trypsin & chymotrypsin from pancreas Digest lipids (fats) bile from liver & lipase from pancreas Absorption VILLI – small finger-like projections that increase the surface area MICROVILLI – even smaller finger-like projections on the VILLI Capillaries – small blood vessels found on each villus (Absorbs all nutrients )
- 17. The Parts ofSmall intestine 1.Duodenum - most digestion occurs here 2.Jejunum - some digestion and some absorption occur 3.Ileum - mostly absorption
- 18. SMALL INTESTINE • Thesmall intestine is divided • duodenum • jejunum • ileum.
- 19. • Pancreas has2 functions: a) Endocrine functions: secretes insulin and glucagon from islets of Langerhans b) Exocrine function: secretion of pancreatic juice • It has 2 components: aqueous and enzymatic components. • Aqueouscomponent(contains HCO3) is important for neutralizing stomach acid in the duodenum so pancreatic enzymes can function properly • Enzymatic component is essential for the proper digestion and absorption of carbohydrates, fats, and proteins • Pancreatic enzymes include trypsin, chemotrypsin, lipase, and amylase Functions of the Pancreas
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- 21. Liver Functions of theLiver: 1)Metabolic regulation •Store absorbed nutrients, vitamins •Release nutrients as needed 2)Hematological regulation •Plasma protein production •Remove old RBCs 3)Production of bile •Required for fat digestion and absorption
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- 24. The Large Intestine(colon) • Much shorter than small intestine, but has larger diameter Functions 1. Goblet cells: create mucus that lubricates colon and protects mucosa. 2. Absortive cells: Maintain water balance, solidify feces, absorb vitamins and some ions • Prepare waste for expulsion 28
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- 27. Digestive System – Ruminants– Mouth, esophagus, liver, pancreas, gall bladder, small intestine, and large intestine have functions similar to monogastrics.
- 29. Reticulum • Holding areafor feed after it passes down esophagus. • Provides additional area for fermentation. • Contains microorganisms, like rumen • Collection compartment for foreign objects. • Helps open and close rumen. • Minimal separation with rumen.
- 30. Rumen • Largest ofthe four components. • On the left side of the animal. • Storage site and fermentation . • Houses millions of microorganisms. • Lined with millions of finger-like projections (papillae) that are needed for absorption. “paunch”
- 31. Omasum • A heavy,hard organ that has many folds or leaves. • Little, if any digestive activity. • Grinds feed particles. • Removes moisture. “many piles”
- 32. Abomasum • True, glandularstomach • Functions similarly to monogastric stomach • Secretes gastric juices which aid in digestion. Infected with barber pole worms
- 33. Organs of theDigestive System – Hind Gut Fermentors – Mouth, esophagus, stomach, liver, pancreas,, and small intestine have similar functions as compared to monogastrics. Horse doesn’t have gall bladder
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- 36. Organs of theDigestive System – Hind Gut Fermentors – • Large Intestine ►Major difference between monogastrics and hind gut fermentors is the large intestine. ►Large intestine is exceptionally large and complex compared to monogastrics and ruminants.
- 37. The large intestineof hind gut fermentors is analogous to the rumen in ruminants. ►Microbes digest structural carbohydrates (cellulose, hemicellulose) and soluble carbohydrates that escape digestion in small intestine to VFA’s. 🗸 VFA’s absorbed from large intestine and utilized by the animal. ►Microbial protein produced in large intestine is wasted (only very limited absorption from large intestine).
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- 39. Avian Digestive Systems •Mouth – no teeth – Salivation excretion moistens food • Esophagus – has a modification called the “crop” which stores and moistens food – connects mouth and stomach
- 40. 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
- 41. 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
- 43. Digestive System Comparisons FunctionMonogastric Ruminants Hind Gut Fermentors Digest and extract energy from cellulose Very limited (large intestine) Yes (rumen/reticulum) Yes (large intestine) Utilize dietary sugar sources directly Yes (absorbed as glucose) No (fermented to VFA’s) Yes (absorbed as glucose) Utilize protein from feeds directly Yes Limited (most converted to microbial protein) Yes Utilize fat from feeds directly Yes Some (most fermented to VFA’s) Yes Utilize microbial protein No Yes (60-80% of AA from microbes) No
- 45. Human Cattle BirdHorses Teeth 32 32 0 40-42
- 46. Organs of digestivesystem Comparisons Ruminant • Mouth • Esophagus • Stomach – Reticulum – Rumen – Omasum – Abomasum • Small intestines • Large intestines Monogastric • Mouth • Esophagus • Stomach • Small intestines • Large intestines Liver Pancreas Liver Pancreas
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