PRINCIPLES OF HUMAN PHYSIOLOGY THIRD EDITION Cindy L. Stanfield | William J. Germann PowerPoint ® Lecture Slides prepared by W.H. Preston, College of the Sequoias Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. 21 Part A The Endocrine System: Regulation of Energy Metabolism and Growth

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Anabolism Molecules used in generating energy also used in synthesis of large molecules Whether used for energy or synthesis depends on body needs Mechanisms exist to regulate pathways

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Energy Intake, Utilization, and Storage Following intake, nutrients can be Catabolized for energy Substrates for new molecules Stored for energy (glycogen and fat)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Uptake, Utilization, and Storage of Energy in Carbohydrates Absorbed carbohydrates Monosaccharides Circulating in blood Glucose Usable carbohydrates Glucose  energy Glycogen  stores energy Polysaccharides  membranes

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Uptake, Utilization, and Storage of Energy in Proteins Absorbed forms Tripeptides Dipeptides Amino acids Circulating in blood Amino acids Usable form Amino acids  proteins Amino acids  energy

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Uptake, Utilization, and Storage of Energy in Lipids Absorbed lipids Triglycerides Circulating in blood in lipoproteins Fatty acids Monoglycerides Usable lipids Fatty acids  energy Triglycerides  store energy Steroids and phospholipids

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Biomolecules Figure Fatty acids Fatty acids Glycogen CarbohydratesProteinsLipids Protein Glucose Urea Liver Amino acids Glycerol Triglyceride NH 3 2 NH 3 Other metabolism CO 2 + H 2 O + energy CO 2 + H 2 O + NH 3 + energy CO 2 + H 2 O + energy LPL + Monoglyceride Lipoproteins + 1 (a)(b)(c)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Delivery of Lipids to Cells Lipids transported in blood From GI to liver, adipose tissue and other cells in chylomicrons From liver to body cells in VLDLs Lipoprotein lipase located on inner surface of capillaries Triglycerides  monoglyceride + 2 Fatty Acids Fatty acids diffuse into cells Monoglycerides go to liver for further metabolism

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Summary of Biomolecules Table 21.1

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Forms of Energy Figure 21.2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Basal Metabolic Rate Basal metabolic rate (BMR) = rate of energy expenditure of a person awake, resting, lying down, and fasted for 12 hours Represents minimum energy expenditure necessary to maintain body functions Metabolic rate increases with increases in activity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Energy Balance Varies During Absorptive and Postabsorptive States Energy balance not continuous Energy input intermittent Absorptive state 3–4 hours following meal Nutrients in bloodstream plentiful from absorption Postabsorptive Between meals Energy stores must be mobilized

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Absorptive State Energy input > output as nutrients absorbed Glucose = primary energy source for cell Excess nutrients taken up will be stored Liver and muscle store glycogen Adipose tissue stores triglycerides

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Postabsorptive State Energy input < output Glucose spared for nervous system Other tissues use fatty acids or other sources for energy Stored nutrients broken down and mobilized

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Absorptive State Reactions Figure 21.3 Liver and adipose tissue GlycerolGlycogen Triglycerides ProteinCO 2 + H 2 O + energy GlucoseFatty acids Liver Fatty acids Amino acids Most body cells Liver and muscleMuscle and other cells Blood Absorption of small nutrients

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Table 21.2 Energy Stores Note: Glycogen stores in liver and muscle = 500 grams Note: Triglyceride stores in adipose tissue is unlimited

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Postabsorptive State Reactions Figure 21.4 Stored macromolecules CO 2 + NH 3 + H 2 O + energyCO 2 + H 2 O + energy Proteins Amino acids Glycogen Ketones Glucose Triglycerides Muscle and other cells Adipose tissue GlycerolFatty acidsLactate, pyruvate Muscle Glucose Amino acids Blood Fatty acids Non-nervous tissueNervous tissue Liver

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Regulation of Absorptive and Postabsorptive Metabolism Hormonal regulation Insulin = hormone of absorptive state Glucagon = hormone of postabsorptive state Other less important regulators Epinephrine Sympathetic nervous system

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Insulin Peptide hormone secreted from beta cells of pancreas islets of Langerhans Promotes synthesis of energy storage molecules (anabolic reactions) Promotes glucose uptake by body cells

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Insulin Secretion Secretion increased during absorptive state Increase glucose in plasma Increase [amino acids] in plasma Parasympathetic nervous system Glucose-dependent insulinotropic peptide (GIP) Secretion decreased during postabsorptive state Sympathetic nervous system activity Epinephrine

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Actions of Insulin Figure 21.5

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Glucagon Peptide hormone secreted from alpha cells of pancreas islets of Langerhans Promotes breakdown of energy storage molecules (catabolic reactions) Promotes glucose sparing for nervous system by diverting body cells to utilizing other sources of energy

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Glucagon Secretion Secretion increased during postabsorptive state Sympathetic nervous system Epinephrine Secretion decreased during absorptive state Increase glucose in plasma

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Actions of Glucagon Figure 21.6

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Insulin and Glucagon Release Table 21.3

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Regulation of Blood Glucose Levels Normal blood glucose = 70–100 mg/dL Hyperglycemia = glucose > 140 mg/dL Hypoglycemia = glucose < 60 mg/dL Blood glucose levels maintained primarily by actions of insulin and glucagon

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Glucose Regulation Via Insulin Figure 21.7a Insulin secretion Glucose uptake into cells Beta cells in pancreas Plasma glucose Negative feedback Most tissuesLiver and muscle Liver Glycogen synthesis Glycogenolysis Gluconeogenesis (a)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Glucose Regulation Via Glucagon Figure 21.7b Adipose tissue Glucagon secretion Glucose spared Plasma fatty acids Lipolysis Alpha cells in pancreas Plasma glucose Negative feedback Glycogenolysis Liver Gluconeogenesis (b)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings. Glucose Regulation Via Glucagon Figure 21.7b, step 10 Adipose tissue Glucagon secretion Glucose spared Plasma fatty acids Lipolysis Alpha cells in pancreas Plasma glucose Glycogenolysis Liver Gluconeogenesis (b)