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Course objectives

Course objectives. Understand how living and non-living environments are interrelated Understand how cells function Understand how the human body functions Understand principles of heredity. Digestion. Chapter 34. Animal Diets. Characterized by dominant food resource 3 main categories

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Course objectives

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  1. Course objectives • Understand how living and non-living environments are interrelated • Understand how cells function • Understand how the human body functions • Understand principles of heredity

  2. Digestion Chapter 34

  3. Animal Diets • Characterized by dominant food resource • 3 main categories • Herbivores • Carnivores • omnivores

  4. Teeth Aid in Digestion • Teeth types process food differently

  5. Dentition • Varies according to diet • Incisors- tearing • Canine- tearing • Premolar- tearing • Molar- grinding

  6. Digestive Compartments • Prevent digestion of own tissues • Food vacuoles- Paramecium • Digestive sac- hydra • Incomplete digestive tract • Digestive tubes- most animals • Complete digestive tract • Vary in complexity

  7. Digestive Compartments • Prevent digestion of own tissues • Tube within a tube design

  8. Tube within a tube design

  9. Nutrition Introduction • Heterotrophs • Provides molecules body Needs to function

  10. Food Processing • Ingestion • Mechanical digestion • Secretion • Chemical digestion • Absorption • Excretion • Movement

  11. Ingestion • Intake of food source ie organic & inorganic molecules • Food, water & minerals • Physical action

  12. Mechanical Digestion • Physical process • Physical reduction of food size • Tongue, teeth, churning (mixing) of stomach & intestine

  13. Secretion • Production & release of digestive chemicals & enzymes • Ex production of salivary amylase to chemically break down food particles

  14. Chemical Digestion • Break down of food • Chemical & enzymatic breakdown • Absorbable units- monomers • Monosaccharides • Amino acids • Fatty acids

  15. Absorption • Transport of monomers through intestinal cells into blood & lymph

  16. Movement • Transfer of ingested particles through the digestive tract • Peristalsis • Wave-like smooth muscle contractions of the digestive tract • Pushes solids & liquids through tract

  17. Excretion • Removal of indigestible substances • Defecation- removing solid wastes

  18. Digestive System • Gastrointestinal tract • Accessory organs

  19. Gastrointestinal Canal • Tube within a tube design- 27 Ft! • Specialized regions perform specific functions • Sphincters- regulation • Oral cavity-pharynx-esophagus-stomach-small intestine-large intestine (colon & rectum)- anus

  20. Accessory Organs • Aid in food processing as it travels through the digestive tract • Food does not pass through accessory structures • Teeth • Tongue • Salivary glands • Liver • Gall bladder • Pancreas

  21. Oral Cavity • Mechanical digestion • Teeth Breaks down food • Chemical digestion • Salivary gland • Introduces salivary amylase • Starch enzyme • Lubrication • Tongue • Bolus

  22. Taste Buds • Sensory nerve cells lining surface of papillae • Sensitive to 5 taste modalities • Sweet • Sour • Bitter • Salty • Umami • Water

  23. Pharynx • Intersection of digestive & respiratory tracts • Connects mouth with esophagus • Uvula & Epiglottis- regulation

  24. Swallowing

  25. Esophagus • Muscular connective tube • 1 ft • Peristalsis • Moves bolus 1-2 sec • Stimulated by Chemical cues

  26. Stomach • Elastic & folded to maximize capacity • (approx 2L) • Rugae- folds for expansion • Temporary storage • 2-6 hours • Mechanical digestion • Churning • Chemical digestion • Alexis st. martin- 1822 • Protein digestion

  27. Rugae are Stretchy

  28. Gastric Juice • Digestive fluid secreted by stomach lining • Hydrochloric acid • Pepsin- digestive enzyme • Mucus • When mixed with food = acid chyme • Gastric sphincters- prevent backflow • Acid reflux • Highly Regenerative lining

  29. Acid Reflux • Esphogeal sphincter Prevents reflux (backflow) of stomach (gastric) substances • Improper closing of sphincter • Gastroesophageal reflux disorder (GERD) • Acid reflux- “heart burn” painful irritation of esophagus

  30. Gastric Ulcers

  31. Small Intestine • Small diameter • Approx 6 meters (20 ft long) • Majority of chemical digestion • Receives secretions from • Pancreas, Liver & gall bladder, Intestine lining • Absorption In lower regions of sm intestine • 90% nutrient absorption • Vast surface area • 300 m2 • Via folds

  32. Lots of blood supply for absorption of nutrients

  33. Pancreas Function • Produce pancreatic juice • Secretes hormones that regulate blood sugar levels • Sodium bicarbonate • Neutralizes acid chyme • Enzymes • Pancreatic Amylase- Carbohydrates • Pancreatic lipases- lipids • Trypsin & chymotrypsin- proteins

  34. Liver & Gall Bladder • Aid in digestive function • Liver • Largest abdominal organ (~3 lbs) • Filters toxins, nutrients & minerals from blood • Stores glycogen- regulates blood sugar levels • Produces bile • Gall Bladder • Stores & secretes bile

  35. Bile Emulsifies Lipids

  36. Duodenum of Small Intestine • First 10 inches of small intestine • Receives acid chyme from stomach • Neutralizes pH from 2 to 7 • Bulk of chemical digestion

  37. Large Intestine • Relative short length (1.5m), but wide • Comprised of colon & rectum • Accessory- appendix • Primary functions • Absorption of water & electrolytes • Absorption of vitamins (bacteria) • Liberated by resident bacterial flora • Vit B & K • Compaction & elimination of waste • Indigestible material= feces • Rectum- storage

  38. Appendix & Appendicitis

  39. Colon Fauna • Variety of prokaryotes- bacteria • Good bacteria produce vitamins • “stomach bug” bacterial infection • Diarrhea- colon not working • Results in Dehydration • Flushes out Bacteria • Constipation • Slow peristalsis • Lack of exercise or fiber

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