1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & Physiology SIXTH EDITION Frederic H. Martini PowerPoint ® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii Chapter 25, part 1 Metabolism and Energetics

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Learning Objectives Understand the functions of metabolic and anabolic dynamics Summarize the characteristics of the absorptive and postabsorptive metabolic states Explain what constitutes a balanced diet and why such a diet is important Define metabolic rate and discuss the factors involved in determining an individual’s BMR

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 25-1 An Overview of Metabolism

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Metabolism is all the chemical reactions that occur in an organism Cellular metabolism Cells break down excess carbohydrates first, then lipids Cells conserve amino acids 40% of the energy released in catabolism is captured in ATP Rest is released as heat Metabolism

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.1 Figure 25.1 An Introduction to Cellular Metabolism

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Performance of structural maintenance and repairs Support of growth Production of secretions Building of nutrient reserves Anabolism

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.2 Figure 25.2 Metabolic Turnover and Cellular ATP Production

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings cells provide small organic molecules for their mitochondria Mitochondria produce ATP used to perform cellular functions Cells and Mitochondria

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings No one cell of the human body can perform all necessary homeostatic functions Metabolic activities must be coordinated Homeostasis

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Liver The focal point for metabolic regulation and control Adipose tissue Stores lipids primarily as triglycerides Skeletal muscle Substantial glycogen reserves Body has five metabolic components

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neural tissue Must be supplied with a reliable supply of glucose Other peripheral tissues Able to metabolize substrates under endocrine control Body has five metabolic components

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The period following a meal Nutrients enter the blood as intestinal absorption proceeds Liver closely regulates glucose content of blood Lipemia commonly marks the absorptive state Adipocytes remove fatty acids and glycerol from bloodstream Glucose molecule are catabolized and amino acids are used to build proteins The absorptive state

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.15 The Absorptive State Figure 25.15

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings From the end of the absorptive state to the next meal Body relies on reserves for energy Liver cells break down glycogen, releasing glucose into blood Liver cells synthesize glucose Lipolysis increases and fatty acids released into blood stream Fatty acids undergo beta oxidation and enter TCA The Postabsorptive state

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amino acids either converted to pyruvate or acetyl-CoA Skeletal muscles metabolize ketone bodies and fatty acids Skeletal muscle glycogen reserves broken down to lactic acid Neural tissue continues to be supplied with glucose The Postabsorptive state

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.16 Metabolic Reserves Figure 25.16a

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.17 The Postabsorptive State Figure 25.17

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 25-7 Diet and Nutrition

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nutrition Absorption of nutrients from food Balanced diet Contains all the ingredients necessary to maintain homeostasis Prevents malnutrition Diet and Nutrition

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Food groups and food pyramids Used as guides to avoid malnutrition Food

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Six basic food groups of a balance diet arranged in a food pyramid Milk, yogurt and cheese Meat, poultry, fish, dry beans, eggs, and nuts Vegetables Fruits Bread, cereal, rice and pasta Base of pyramid Fats, oils and sweets Top of pyramid Food Groups

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.18 Figure 25.18 The Food Pyramid and Dietary Recommendations

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings N compounds contain nitrogen Amino acids, purines, pyrimidines, creatine, porphyrins Body does not maintain large nitrogen reserves Dietary nitrogen is essential Nitrogen balance is an equalization of absorbed and excreted nitrogen Nitrogen balance

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Act as co-factors in enzymatic reactions Contribute to osmotic concentrations of body fluids Play a role in transmembrane potentials, action potentials Aid in release of neurotransmitters and muscle contraction Assist in skeletal construction and maintenance Important in gas transport and buffer systems Aid in fluid absorption and waste removal Minerals

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Are needed in very small amounts for a variety of vital body activities Fat soluble Vitamins A, D, E, K Taken in excess can lead to hypervitaminosis Water soluble Not stored in the body Lack of adequate dietary intake = avitaminosis Vitamins

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 25-8 Bioenergetics

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The study of acquisition and use of energy by organisms Energy content of food expressed in Calories per gram (C/g) Bioenergetics

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Catabolism of lipids yields 9.46 C/g Catabolism of proteins and carbohydrates yields ~4.7 C/g Food and energy

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Total of all anabolic and catabolic processes underway Basal metabolic rate (BMR) is the rate of energy used by a person at rest Metabolic rate

30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostatic regulation of body temperature Heat exchange with the environment involves four processes: Radiation Conduction Convection Evaporation Thermoregulation

31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.19 Routes of Heat Gain and Loss Figure 25.19

32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Preoptic area of hypothalamus acts as thermostat Heat-loss center Heat-gain center Mechanisms for increasing heat loss include: Peripheral vasodilation Increase perspiration Increase respiration Behavioral modifications Regulation of heat gain and loss

33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Decreased blood flow to the dermis Countercurrent heat exchange Shivering thermogenesis and nonshivering thermogenesis Differs by individuals due to acclimatization Mechanisms promoting heat gain

34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.20 Countercurrent Heat Exchange Figure 25.20

35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Problems in infants Lose heat quickly due to their small size Do not shiver Use brown fat to accelerate lipolysis - energy escapes as heat Variations in adults Use subcutaneous fat as an insulator Different hypothalamic thermostatic settings Thermoregulation

36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fever is body temperature greater than 37.2 o C Can result from a variety of situations including: Heat exhaustion or heat stroke Congestive heart failure Impaired sweat gland activity Resetting of the hypothalamic thermostat by circulating pyrogens Pyrexia is elevated body temperature

37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Why cells need to synthesis new organic components The characteristics of the absorptive and postabsorptive metabolic states What constitutes a balanced diet and why such a diet is important Metabolic rate and the factors involved in determining an individual’s BMR You should now be familiar with: