1. Temperature Regulation
Chapter 25
Nutrition, Metabolism,
Temperature Regulation

2. Nutrients Chemicals used by body Classes Food Guide Pyramid
Carbohydrates, proteins, lipids, vitamins, minerals, water
Food Guide Pyramid
USDA recommends
Kilocalories
Measure of energy supplied by food and released through metabolism

3. Carbohydrates Monosaccharides Disaccharides Polysaccharides (complex)
Include glucose, fructose, galactose
Disaccharides
Include sucrose, maltose, lactose
Polysaccharides (complex)
Include starch, glycogen, cellulose
Disaccharides and Polysaccharides
Converted to glucose (used for energy or stored as glycogen or fats)

4. Lipids
Triglycerides (95%): Used for energy to produce ATP or stored in adipose tissue, liver
Saturated fats: Meat fats, whole milk, cheese, eggs
Unsaturated fats: Olive and peanut oil
Cholesterol: Steroid found in liver, egg yolks but not found in plants
Phospholipids: Major components of plasma membranes

5. Proteins Chains of amino acids Functions Kinds
Essential (9): Must be obtained in diet
Nonessential: Body can synthesize
Functions
Protection (antibodies), regulation (enzymes, hormones), structure (collagen), muscle contraction (actin, myosin), transportation (hemoglobin, ion channels)

6. Recommended Amounts Carbohydrates Lipids Proteins
60% of daily intake of kilocalories
Lipids
30% or less of total daily kilocalories
Proteins
10% of total kilocalories per day

7. Vitamins Function as coenzymes or parts of coenzymes
Organic molecules that exist in minute quantities in food
Essential vitamins must be obtained by diet
Classifications
Fat soluble: Vitamins A,D,E,K
Water-soluble: B and C

8. Minerals Inorganic Necessary for normal metabolic functions Functions
Establish resting membrane potentials, generate action potentials, add strength to bones and teeth, buffers, involved in osmotic balance
Obtained from animal and plant sources

9. Metabolism Total of all chemical changes that occur in body
Anabolism: Energy-requiring process where small molecules joined to form larger molecules
Catabolism: Energy-releasing process where large molecules broken down to smaller
Energy in carbohydrates, lipids, proteins is used to produce ATP through oxidation-reduction reactions

10. Catabolic and Anabolic Reactions

11. Cellular Metabolism

12. Carbohydrate Metabolism
Glycolysis
Breakdown of glucose into 2 pyruvic acid molecules
Phases
Input of ATP
Sugar cleavage
NADH production
ATP and pyruvic acid production

13. Glycolysis

14. Glycolysis

15. Anaerobic Respiration
Breakdown of glucose in absence of oxygen
Produces 2 molecules of lactic acid and 2 molecules of ATP
Phases
Glycolysis
Lactic acid formation
Cori cycle
Process of converting lactic acid to glucose

16. Aerobic Respiration
Breakdown of glucose in presence of oxygen to produce carbon dioxide, water, 38 ATP molecules
Most of ATP molecules to sustain life are produced this way
Phases
Glycolysis, acetyl-CoA formation, citric acid cycle, electron-transport chain

17. Aerobic Respiration

18. Electron-Transport Chain

19. Lipid Metabolism
Adipose triglycerides are broken down and released as free fatty acids
Free fatty acids are taken up by cells and broken down by beta-oxidation into acetyl-CoA which
Can enter citric acid cycle
Can be converted to ketone bodies

20. Protein Metabolism
New amino acids are formed by transamination, transfer of an amine group to keto acid
Amino acids are used to synthesize proteins
If used for energy, ammonia is produced as a by-product of oxidative deamination
Ammonia is converted to urea and excreted

21. Amino Acid Metabolism
Once absorbed in body, amino acids quickly taken up by cells
Amino acids are used to synthesize proteins or as a source of energy
Amino acids not stored in body

22. Amino Acid Reactions

23. Interconversion of Nutrient Molecules
Glycogenesis
Excess glucose used to form glycogen
Lipogenesis
When glycogen stores filled, glucose and amino acids used to synthesize lipids
Glycogenolysis
Breakdown of glycogen to glucose
Gluconeogenesis
Formation of glucose from amino acids and glycerol

24. Interconversion of Nutrient Molecules

25. Metabolic States Absorptive state Postabsorptive state
Period immediately after eating when nutrients absorbed through intestinal wall into circulatory and lymphatic systems (about 4 hours after each meal)
Postabsorptive state
Occurs late in morning, afternoon, night after absorptive state concluded
Blood glucose levels maintained by conversion of other molecules to glucose

27. Absorptive State

28. Postabsorptive State

29. Metabolic Rate
Total amount of energy produced and used by body per unit of time
Estimated by amount of oxygen used per minute
Components
Basal metabolic rate
Energy used at rest, 60% of metabolic rate
Thermic effect of food
Energy used to digest and absorb food, 10%
Muscular activity
Energy used for muscle contraction, 30%

30. Body Temperature Regulation
A balance between heat gain and loss
Heat is produced through metabolism
Heat is exchanged through radiation, conduction, convection, evaporation
The greater the temperature difference between body and environment, the greater the rate of heat exchange
Regulated by a “set point” in hypothalamus

31. Heat Exchange

32. Temperature Regulation