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Bio 449 Lecture 29 – Digestive Physiology I Nov. 17, 2010
Introduction Components of food Overview of GI system Digestion and absorption Components General structure of the GI "tube" Function and control of the GI tract Physical breakdown of food Mouth Esophagus Stomach Terms to Know Triglyceride Gastrointestinal system Digestion Absorption Serosa Submucosa Mucosa Lumen Peristalisis Motility Mastication Parietal cells Chief cells Goblet cells Pepsin(-ogen) Gastrin Chyme Pyloric sphincter Terms to Know Carbohydrate Monosaccharide Disaccharide Polysaccharide Starch Glycogen Readings Lectures 29-30: Chapter 21
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Components of food
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Simple Carbohydrates Fig. 2-7 Glucose Fructose + Galactose
Glucose (dextrose) Galactose* MONOSACCHARIDES Glucose Fructose + Galactose Sucrose (table sugar) Maltose Lactose DISACCHARIDES Fig. 2-7
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Complex Carbohydrates
Animals Plants Yeasts and bacteria POLYSACCHARIDES Chitin (invertebrates only) Glycogen Glucose molecules Cellulose Starch Dextran Fig. 2-7
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Lipids + Fig. 2-8 Fatty acid Glycerol MONOGLYCERIDE DIGLYCERIDE
TRIGLYCERIDE + G L Y C E R O Oleic acid, a monounsaturated fatty acid Linolenic acid, a polyunsaturated fatty acid Palmitic acid, a saturated fatty acid Fig. 2-8
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Proteins
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Overview of GI system
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Digestion and absorption
SECRETION DIGESTION ABSORPTION MOTILITY Lumen of digestive tract Wall Interstitial fluid Blood Food Fig. 21-2
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Carbohydrate Digestion
Fig
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Protein & Fat Digestion
Fig
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Motility Fig. 21-5 Direction of movement Receiving segment Time zero
Seconds later Contraction Bolus Bolus moves forward No net forward movement Fig. 21-5
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Components of the GI system
Oral cavity Salivary glands Esophagus Pancreas Stomach Small intestine Rectum Large intestine Gallbladder Liver Fig. 21-3
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General structure of the GI tube
Submucosal glands Serosa Submucosa Mucosa Circular muscle Longitudinal muscle Fig. 21-3
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General structure of the GI tube
Epithelium Lymph vessel Artery and vein Mucosa Submucosa Circular muscle Longitudinal muscle Serosa Muscularis externa Fig. 21-3
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Rugae: Surface folding increases area
Stomach anatomy Esophagus Antrum Pylorus Rugae: Surface folding increases area Fundus Diaphragm Body Fig. 21-3
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Gastric motility
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Rugae: Surface folding increases area
Stomach anatomy Esophagus Antrum Pylorus Rugae: Surface folding increases area Fundus Diaphragm Body Fig. 21-3
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Gastric glands Surface epithelial cells pit Goblet cells Chief cells
Parietal cells
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