BIO 102 Anatomy and Physiology: Nutrition (Ch24) Marieb 11ed ACC fa22 PDF

BIO 102 ANATOMY AND PHYSIOLOGY Chapter 24: Nutrition and Metabolism Professor Caitlin Burns 1 Learning Objectives: 1. Define and describe the terms nutrient, macronutrient, micronutrient, essential nutrient, RDA, caloric balance,...

BIO 102 ANATOMY AND PHYSIOLOGY Chapter 24: Nutrition and Metabolism Professor Caitlin Burns 1 Learning Objectives: 1. Define and describe the terms nutrient, macronutrient, micronutrient, essential nutrient, RDA, caloric balance, nitrogen balance, BMI, BMR, calorie, and metabolism (anabolism, catabolism). 2. Describe the anabolic and catabolic processes of carbohydrate, lipid, and protein metabolism, explain the processes that relate to the absorptive (fed) and post-absorptive (fasted) states, and identify the major hormones associated with those states. 3. Explain how neural and hormonal factors regulate food intake. 2  Nutrients chemical substances supplied by the environment required for survival (used for growth, repair, or maintenance of the body) Macronutrients Micronutrients Essential Nutrients carbohydrates vitamins human cells proteins minerals cannot fats synthesize include certain fatty acids, amino acids, vitamins 3 Energy Values of Food Calorie (kilocalorie, big calorie) – amount of heat energy needed to raise the temperature of 1 kg of water by 10 C Carbohydrates 4.1 Calories per gram Proteins 4.1 Calories per gram Lipids 9.5 Calories per gram 4  5 Figure 24.3 Three stages of metabolism of energy-containing nutrients Carbohydrates 6 Utilization of Carbohydrates Disaccharides – sucrose, lactose, and maltose Monosaccharides – glucose, fructose, galactose Glucose is the body’s CHO energy source oxidized for energy production of certain molecules (ribose, deoxyribose) stored in liver and muscles as glycogen converted to fats and stored in adipose tissue 7  Carbohydrate Metabolism 8 Figure 24.12 Quick summary of carbohydrate reactions  9 Figure 24.13 Glycogenesis and glycogenolysis Lipids 10 Utilization of Lipids The liver uses fatty acids to synthesize a variety of lipids 11  Summary of Lipoproteins 12 Figure 24.24 Composition and function of lipoproteins  Lipid Metabolism 13 Figure 24.14 Quick summary of lipid reactions  14 Figure 24.16 Lipid metabolism Proteins 15  Essential Amino Acids cannot be synthesized by the body Figure 24.2 Essential amino acids 16 Utilization of Proteins build cell structures regulation of water balance enzymes control of pH hormones formation of antibodies transport of oxygen 17  Amino acid catabolism 18 Figure 24.18 Quick summary of amino acid catabolism  19 Figure 24.17 Processes that occur when amino acids are utilized for energy  Nitrogen Balance Homeostatic state where rate of protein synthesis equals rate of breakdown and loss Positive nitrogen balance: synthesis exceeds breakdown normal in children, pregnant women, tissue repair Negative nitrogen balance: breakdown exceeds synthesis stress, burns, infect., injury, poor dietary proteins, starvation The body neither stores nor maintains reserves of N. There’s only about 1 kg of N in body at any one time. During starvation, N-containing compounds, like skeletal muscle, are conserved; CHO and fats are metabolized first (protein-sparing effect). Order of usage: CHO, fat, protein. 20  21 Figure 24.19 Interconversion of carbohydrates, fats, and proteins  Absorptive (“Fed”) State 22 Figure 24.20 Major events and principal metabolic pathways of the absorptive state  Absorptive (“Fed”) State 23 Figure 24.20 Major events and principal metabolic pathways of the absorptive state  Post-absorptive (“Fasted”) State 24 Figure 24.22 Major events and principal metabolic pathways of the postabsorptive state  The Post-absorptive (“Fasted”) State 25 Figure 24.22 Major events and principal metabolic pathways of the postabsorptive state 26  Energy Requirements Basal metabolic rate (BMR) rate at which body expends energy at rest (kcal/hr) primarily reflects energy needed to support activities of organs varies with gender, body size, body temperature, and endocrine function proportional to body weight falls 10% during sleep, falls 40% during prolonged starvation Energy needed to maintain BMR to support resting muscular activity to maintain body temperature for growth in children and pregnant women BMR is greatly affected by circulating thyroid hormone levels 27 Energy Balance occurs when caloric intake in the form of food equals caloric output from BMR and muscular activities positive energy balance leads to weight gain negative energy balance leads to weight loss Body Mass Index (BMI)* = Wt (kg) / Height2 (m) Thin < 18.5 Healthy or Normal 18.5 – 24.9 Overweight 25.0 – 29.9 Obese 30.0 – 39.9 Morbidly Obese ³ 40.0 * Source: World Health Organization 28  Regulation of Appetite 29 Figure 24.25 Model for hypothalamic command of appetite and food intake  Become educated Visit USDA’s MyPlate.gov guidelines represented as portions on a dinner plate Basic dietary principles Eat only what you need Eat less overall Eat healthy food Read food labels Reduce fast food intake Exercise 30