The Digestive system

1. The Digestive system

3. Carnivore: Herbivore: Omnivore: Meat eater Plant eater Eats both plants AND animals

4. Teeth C Incisors- foremost teeth used to bite into food Canines- largest teeth, used for tearing food (if present in mouth) Premolars & Molars- crush and grind food

5. Teeth of different species - IncisorsCaninesPremolarsMolars Upper 6 2 8 4 Lower 6 2 8 6 Upper 6 2 8 4 Lower 6 2 8 6 Upper 0 0 6 6 Lower 6 2 6 6 DOG HORSE CATTLE

6. Saliva: • produced by FOUR salivary glands. • Contains enzyme amylase which begins to break down starch into simple sugar, maltose. • Helps maintain stable pH in mouth. • Makes food easier to swallow. • Tongue: • Helps to obtain food and moves it around in mouth to aid in chewing • Bolus- food that is ground into a small ball and ready to be swallowed.

7. Esophagus- • Delivers food through neck, chest cavity, and diaphragm into stomach • Food is propelled by peristalsis (set of muscle contractions in a hollow organ that propels its contents) • Stomach- • Secretes gastric juices and muscle contractions to break down food. • Little absorption occurs here • Monogastric- single stomach Examples….. • Ruminant- four compartment stomach Examples…..

8. Liver & Pancreas- • Controls blood sugar levels and stores certain vitamins and iron • Both secrete digestive enzymes needed for further digestion • Small Intestine- • Lined with finger-like projections called villi, which aid in absorption of nutrients • Much of digestion and absorption of nutrients occur within small intestine • THREE PARTS: 1. Duodenum, 2. Jejunum, 3. Ileum Bo

9. Large Intestine- • Absorbs water from material that will become feces • Three parts: Colon, Cecum, Rectum • **Note: Horses have a well-developed large intestine • Cecum is very long- 1.25 meters (4.1 Feet), can hold 25-30 Liters

10. Digestive Enzymes and hormones SecretionSourceLocationAction Salivary amylase Salivary glands Mouth Digests Starches HCI Stomach Stomach Breaks down protein, activates pepsin Pepsin Stomach Stomach Digests protein Trypsin Pancreas Small Intestine Digests protein Lipase Pancreas Small Intestine Digests fat

11. Digestive Enzymes and hormones SecretionSourceLocationAction Amylase Pancreas Small Intestine Digests starches Gastrin Stomach Stomach Increases HCI release Secretin Duodenum Liver Increases bile production by the liver Gastric inhibitary Duodenum Stomach Decreases activity of stomach

12. Ruminants Livestock with four-compartment stomachs • Rumen: • First stomach, • large fermentation vat, takes up most of left side of abdomen. • Lined with fingerlike projections called papillae- increase surface area that allows for absorption of nutrients

13. Reticulum: Lining looks like a honeycomb- makes the site that traps any heavy object ingested Placing a magnet in stomach prevents hardware disease by holding metal tight against it- prevents sharp ends from penetrating stomach wall Hardware disease- sharp piece of metal punctures through wall of reticulum into abdomen, penetrates liver or diaphragm and into heart.

14. Omasum: Lined with long folds that prevent large particles from passing and increasing surface area Provides water absorption

15. Abomasum: True Stomach Similar to monogastric stomach Further digestion by cow’s enzymes

16. Rumination: Food taken in quickly by ruminants, then rumen and reticulum contract forcing some of ingested food back through the esophagus and into mouth (regurgitation). The animal then takes time to chew it into finer pieces (cud chewing)

17. Colic- Abdominal illness in horses Symptoms- horse will turn and look or kick at their sides, lie down and get up frequently or roll to relieve pain. Common causes are impaction of food in small intestine, torsion (twist) of small intestine, extreme gas, excessive consumption of sand. Bloat- Large, gaseous distention of rumen (common in cattle). Cows must periodically belch to release the gas from the rumen; if not, bloat will result. In worst cases, a needle needs to be inserted in the cow’s side to relieve the gas. **Both can be fatal**

18. 6 classes of nutrients B • Carbohydrates: • Supply vitamin E • Provide structure within a cell • Supply fiber and bulkiness to diet • Provides glucose to maintain blood sugar levels • Needed to complete metabolism of fat Monosaccharide: simple sugars (Ex. Glucose, fructose) Disaccharides: two sugars (Ex. Lactose) Polysaccharide: long chains of simple sugars (Ex. Starch, cellulose)

19. Proteins: • Made of chains of Amino Acids • Key role in structure and function of cells • Act as enzymes, hormones, and antibodies • Utilized as a source of vitamin E for animals • Essential amino acids: must be supplied in diet • Include: arginine, histidine, isoleucine, lysine, leucine, methionine, phenylalanine, threonine, tryptophan, valine • Nonessential amino acids: can be synthesized from other Amino Acids • Deficiencies: poor growth, low body weight, poor immunity • Fats: • Immediate supply of E or stored. • Provides a source of E, insulation, and some protection to organs • Produces certain hormones • Increases palatability (tastiness) of food • Needed for absorption of certain vitamins.

20. Water: • Most critical nutrient • A loss of only 10% of the body’s water is a serious health risk • Loss of 15% or more is life threatening • Up to two thirds of the body is water • Provides shape to cells • Helps transport nutrients, wastes, and hormones in blood • Controls body temperature

21. Vitamins Most are needed in small amounts to maintain health and function of animals May act as enzymes or coenzymes Either: Fat soluble: absorbed from intestinal tract with Fat; stored in body- A, D, E, K Water soluble: not stored in body, need to be taken on daily basis Eight Vitamin B’s and C Antioxidant (Vitamins A, C, E- protect lipid membranes of cells

22. Vitamin Function A Pigment of retina, night vision, healthy cell function D Synthesized in skin from exposure to UV rays, maintenance & formation of bone and teeth E Associated with selenium, important role in immune & reproductive systems K Blood clotting B1 (Thiamin) Maintenance of nervous system B2 (Riboflavin) Healthy skin B3 (Niacin) Healthy oral tissue

23. Vitamin Function B5 (Pantothenic Acid) Antibody Production B6 (Pyriodozine) Hemoglobin formation Folic Acid Red blood cell formation Biotin Healthy skin & hooves B12 (Cobolamin) Red blood cell production C Wound healing & collagen formation

24. B Minerals Categorized based on relative amounts required by the body Macrominerals- Needed in larger amounts Ca, K, Na, P, Mg, S, Cl Trace Minerals (micronutrients)- Not usually needed in supplement form; often involved in speeding up chemical enzyme reactions and included in hormones.

25. Mineral Function Calcium (Ca) Development of bones & teeth Chloride (Cl) Fluid control in blood Phosporus (P) Bone & teeth; structure of cell membrane Magnesium (Mg) Bone & teeth; hemoglobin production Potassium (K) Needed in protein synthesis; function of nerves and muscle Sodium (Na) Function of nerves & muscles Sulfur (S) In amino acids; methionine & cystine Cobalt (Co) Involved in many enzyme reactions Copper (Cu) Necessary for proper iron metabolism

26. Mineral Function Iodine (I) Portion of thyroid hormone; proper reproductive cycle Iron (Fe) Portion of hemoglobin & oxygen metabolism Manganese (Mn) Involved in bone & connective tissue development Selenium (Se) Antioxidant; needed for healthy immune system Zinc (Zn) Role in bood cell formation & wound healing; needed for healthy skin & hooves; and immune system

27. A Assignment: Research 3 Vitamins and 3 Minerals. For each, write a deficiency symptom and a food that it is found in