Chapter 21

Chapter 21 - Slide 1 Chapter 21: Nutrition and Digestion...

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Unformatted text preview: Slide 1 Chapter 21: Nutrition and Digestion Nutrition and Digestion • Most animals fall into one of three categories: 1. Herbivores 2. Carnivores 3. Omnivores Slide 2 Methods of obtaining food: 1. Suspension feeders 2. Substrate feeders 3. Fluid feeders 4. Bulk feeders Slide 3 1. Suspension feeders Slide 4 Slide 5 2. Substrate feeders Caterpillar Feces 3. Fluid feeders Slide 6 4. Bulk feeders Slide 7 Four stages of food processing Small molecules Pieces of food Mechanical digestion Chemical digestion (enzymatic hydrolysis) Nutrient molecules enter body cells Undigested material Food Ingestion Digestion Absorption Elimination Slide 8 Slide 9 Polymer Monomers Proteindigesting enzymes Amino acids Protein Polysaccharide Carbohydratedigesting enzymes Disaccharide Monosaccharides Nucleic aciddigesting enzymes Nucleic acid Nucleotides Fat-digesting enzymes Fat Glycerol Fatty acids Slide 10 Mouth Tentacle Digestive enzymes released from a gland cell Soft tissues digested Food (Daphnia, a water flea) Food particle engulfed Gastrovascular cavity Food particle digested in food vacuole Alimentary Canal • Most members of Kingdom Animalia have an alimentary canal • Alimentary canal: digestive tract with two openings • Food only travels in one direction • Cells lining different parts of the canals are specialized • Common elements of alimentary canals: Mouth Pharynx (Crop) Stomach (and/or gizzard) Intestine Anus Slide 11 Slide 12 Mouth Pharynx Esophagus Crop Gizzard Anus Intestine Dorsal fold Earthworm Interior of intestine Wall of intestine Slide 13 Esophagus Stomach Anus Mouth Crop Grasshopper Gastric pouches Intestine Slide 14 Stomach Gizzard Intestine Mouth Esophagus Crop Anus Bird Human Digestive System Oral cavity Tongue Mouth Pharynx Salivary glands Esophagus Liver Esophagus Constriction Stomach Gallbladder Pancreas Small intestine Large intestine Rectum Anus Pyloric sphincter Small intestine Slide 15 Slide 16 Human digestion begins in the oral cavity TEETH Incisors Canine Premolars Molars Tongue Salivary glands Opening of a salivary gland duct Saliva is important! • Lubricate food • Neutralize acids • Antibacterial agents • Salivary amylase Slide 17 Slide 18 We can’t breathe and eat at the same time Tongue Bolus of food Pharynx Epiglottis up Esophageal sphincter Larynx Trachea (windpipe) Sphincter contracted Esophagus Slide 19 We can’t breathe and eat at the same time Epiglottis down Epiglottis up Larynx up Esophagus Sphincter relaxed Larynx down Sphincter contracted Peristalsis Slide 20 Muscles contract Bolus of food Muscles relax, allowing passageway to open Stomach Muscles contract, constricting passageway and pushing bolus down Muscles relax Muscles contract Muscles relax Stomach • Temporary food storage • Gastric juice begins to break down food • Acid • Mucus • Enzymes Slide 21 Stomach (cont.) • Surface is highly folded • Pits lead to gastric glands • Three types of cells lining the gastric glands: 1. Mucus cells ­ mucus (protects the stomach lining.) 2. Parietal cells – hydrochloric acid 3. Chief cells ­ pepsinogen Slide 22 Slide 23 Lumen (cavity) of stomach Colorized SEM 2,500× Stomach (cont.) Interior surface of stomach Pits Food particle Release of gastric juice Release of juice (mucus, HCl, and pepsinogen) Epithelium Pepsinogen Mucous cells Stomach Pyloric sphincter Gastric gland Chief cells Parietal cells Pepsin (active HCl enzyme) Stomach (cont.) Food particle Pyloric sphincter Slide 24 Where does digestion begin? • Carbohydrates – (breaks down in the mouth) • Proteins – (breaks down in the stomach) • Lipids – (breaks down in the small intestine) • Nucleic acids – (breaks down in the small intestine) Slide 25 Small intestine Liver Bile Gallbladder Stomach Bile Acid chyme Intestinal enzymes Duodenum of small intestine Slide 26 Pancreatic juice Pancreas Slide 27 Small intestine (cont.) Lumen of intestine Nutrient absorption Vein with blood en route to the liver Nutrient absorption into epithelial cells Microvilli Epithelial cells Muscle layers Amino acids and sugars Lumen Fats Blood capillaries Large circular folds Villi Blood Lymph vessel Lymph Nutrient absorption Epithelial cells Villi Intestinal wall Fatty acids and glycerol Slide 28 Large intestine Large intestine (colon) Small intestine Sphincter End of small intestine Rectum Anus Nutrient flow Appendix Cecum Slide 29 Adaptations of the digestive system Small intestine Small intestine Stomach Cecum Colon (large Intestine) Carnivore Herbivore Slide 30 Ruminants Intestine Omasum Rumen Esophagus Rumen Abomasum Reticulum Healthy Diets • A healthy diet meets three needs 1. Fuel 2. Raw materials 3. Essential nutrients Slide 31 1. Fuel • Every body activity requires energy • Cells oxidize organic molecules to make ATP (energy) • Energy content of food is measured in kilocalories • Females need approx: 1300­1500 kcals/day • Males need approx: 1600­1800 kcals/day Slide 32 3. Essential nutrients • Must be obtained from diet • Undernourished vs. Malnourished • (Not enough calories ) – (Not one or more of your Essential nutrients…) • Four classes: 1. Essential fatty acids 2. Essential amino acids 3. Vitamins 4. Minerals Slide 33 Essential amino acids Essential amino acids Methionine Valine (Histidine) Threonine Phenylalanine Leucine Corn Isoleucine Tryptophan Lysine Beans and other legumes Slide 34 Slide 35 Ingredients: whole wheat flour, water, high fructose corn syrup, wheat gluten, soybean or canola oil, molasses, yeast, salt, cultured whey, vinegar, soy flour, calcium sulfate (source of calcium). Obesity Slide 36 ...
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Chapter 21 - Slide 1 Chapter 21: Nutrition and Digestion...

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