Ch 41 - Chapter 41 - Digestion and Nutrition Understand how...

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Chapter 41 - Digestion and Nutrition Understand how blood glucose level is regulated by negative feedback Understand what essential nutrients are Know what occurs in each part of the human digestive system Know what enzymes digest proteins, fats and carbohydrates, and where they do it Know how and where nutrients and water are absorbed Understand how herbivores are adapted to digest plant diets Digestion and Nutrition 0. Some definitions: 0. Phototrophs use light energy to produce carbohydrates 1. Chemotrophs use inorganic chemical reactions to provide energy 2. Heterotrophs need organic compounds 0. Herbivores feed on plant material 1. Carnivores feed on animal tissues 2. Detritivores feed on decaying plant material Regulation of Glucose 0. When glucose concentration high, pancreas secretes hormone insulin 1. Insulin increases transport across cell walls and stimulates liver to store glucose as glycogen, lowers BGL 2. If glucose low, pancreas secretes glucagon, which breaks down glycogen 3. Diabetes is when BGL is not regulated well (too low or high) Figure 41.3 Fig.ure 41.5 Hormones affecting hunger and appetite The hormone leptin supresses hunger Ghrelin is a hormone that stimulates feeding PYY counters the effects of Ghrelin Insulin also supresses hunger Defective Leptin genes may cause obesity, although 70% is not genetic (e.g., is due to diet Nutritional Requirements
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1. Carbohydrates comprise about 50 % of US diet, provide 4 Kcal/g 2. Lipids about 40 %, at least 3 fatty acids essential, 9 Kcal/g 3. Proteins are remaining 10 %, 9 - 11 amino acids essential, 4.4 Kcal/ g 4. Both fat and water soluble vitamins essential in diet Figure 41.10 Diseases caused by nutritional deficiencies
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This note was uploaded on 12/02/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Ch 41 - Chapter 41 - Digestion and Nutrition Understand how...

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