Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 23 Endocrine Control of Growth and Metabolism

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings About this Chapter How several key hormone pathways influence metabolism How cortisol is produced & regulated; how it impacts many tissues How thyroid hormones are regulated and their effect on targets The role of growth hormone in growth & development Calcium metabolism and its role in bones and cell regulations

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endocrine Control in Review Hypothalamic – pituitary: feedback loop & trophic control Hormones can have receptors on many diverse tissues Usually initiating protein change or synthesis in target cells Problems come from too much or too little hormone

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Aldosterone, sex hormones, cortisol Synthesized from cholesterol–steroid ring Adrenal Cortex: Steroid Hormone Production

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Adrenal Cortex: Steroid Hormone Production Figure 23-2: Synthesis pathways of steroid hormones

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol Effects: Body Responses to Stress Permissive effect on glucagon Memory, learning & mood Gluconeogenesis Skeletal muscle breakdown Lipolysis, calcium balance Immune depression Circadian rhythms

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol Effects: Body Responses to Stress Figure 23-4: Circadian rhythm of cortisol secretion

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Control of Cortisol Secretion: Feedback Loops Figure 23-3: The control pathway for cortisol External stimuli Hypothalamic Anterior Pituitary Adrenal cortex Tissues

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endocrine Control: Three Levels of Integration Figure 7-13: Hormones of the hypothalamic-anterior pituitary pathway

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol: Role in Diseases and Medication Use as immunosuppressant Hyperimmune reactions (bee stings) Serious side effects Hypercortisolism (Cushing's syndrome) Tumors (pituitary or adrenal) Iatrogenic (physician caused) Hypocortisolism (Addison's disease)

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid Gland: Hormones and Iodine Metabolism C-cells – calcitonin (covered later) Follicule cells Amine hormones: thyroxine, T 1, T 2 & T 3  growth  metabolism Thermogenic

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings TH is concerned with: Glucose oxidation Increasing metabolic rate Heat production TH plays a role in: Maintaining blood pressure Regulating tissue growth Developing skeletal and nervous systems Maturation and reproductive capabilities Effects of Thyroid Hormone

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid hormone – the body’s major metabolic hormone Consists of two closely related iodine-containing compounds T 4 – thyroxine; has two tyrosine molecules plus four bound iodine atoms T 3 – triiodothyronine; has two tyrosines with three bound iodine atoms Thyroid Hormone

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid Gland: Hormones and Iodine Metabolism Figure 23-7b: The thyroid gland

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroxine and its precursors: Structure & Synthesis Figure 23-8: Thyroid hormones are made from tyrosine and iodine

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroxine and its precursors: Structure & Synthesis Figure 23-9: Thyroid hormone synthesis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroglobulin is synthesized and discharged into the lumen Iodides (I – ) are actively taken into the cell, oxidized to iodine (I 2 ), and released into the lumen Iodine attaches to tyrosine, mediated by peroxidase enzymes, forming T 1 (monoiodotyrosine, or MIT), and T 2 (diiodotyrosine, or DIT) Iodinated tyrosines link together to form T 3 and T 4 Colloid is then endocytosed and combined with a lysosome, where T 3 and T 4 are cleaved and diffuse into the bloodstream Synthesis of Thyroid Hormone

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings T 4 and T 3 bind to thyroxine-binding globulins (TBGs) produced by the liver Both bind to target receptors, but T 3 is ten times more active than T 4 Peripheral tissues convert T 4 to T 3 Mechanisms of activity are similar to steroids Regulation is by negative feedback Hypothalamic thyrotropin-releasing hormone (TRH) can overcome the negative feedback Transport and Regulation of TH

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings T 3 & T 4 Control Pathways & Diseases from Malfunction Hypothalamus Anterior Pituitary Thyroid Hypothyroidism Goiter (TSH  ) Grave's disease

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T 3 & T 4 Control Pathways & Diseases from Malfunction Figure 23-12: Thyroid hormone pathway

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Growth Hormone (GH): Functions & Malfunctions Polypeptide H from hypothalamus/anterior pituitary  growth (with T 4, sex Hs, paracrines)  metabolism  protein & bone synthesis Regulation – hypothalamus Dwarfism Acromegaly

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.6 Metabolic Action of Growth Hormone

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Growth Hormone (GH): Functions & Malfunctions Figure 23-16: Growth hormone pathway

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Growth H Somatomedins Thyroxin All have receptors on many tissues Stimulate pathways for growth Multiple Hormones Can Target a Cell/Tissue Figure 7-17: A complex endocrine pathway

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epiphyseal plate – new bone growth site Chondrocytes, osteoblasts & calcification build bone Bone Growth and Calcium Metabolism

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Bone Growth and Calcium Metabolism Figure 23-19: Bone growth at the epiphyseal plate

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Maintain [plasma]: from diet, from bone "storage", recycled Key roles: muscle contraction, bone support, cell signaling Calcium Metabolism:

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Calcium Metabolism: Figure 23-20: Calcium balance in the body

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Control of Calcium Balance & Metabolism Figure 23-23: Endocrine control of calcium balance Parathyroid H Calcitrol Vitamin D Sun/diet Calcitonin Thyroid C-cells (Phosphate balance)

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Osteoporosis: Disease of Bone Growth & Calcium Metabolism Figure 23-21: Osteoclasts are responsible for bone resorption Bone reabsorption exceeds deposition Osteoclasts mobilize Ca ++ to plasma Factors: inadequate Ca ++ intake, genes, hormones, smoking

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Summary In addition to insulin and glucagon, metabolism is influenced by hormones from adrenal, thyroid, parathyroid and hypothalamus Cortisol  catabolic activities responding to stress Growth H  anabolic activities to promote growth PTH, cacitrol, & calcitonin balance plasma [Ca++] for bone synthesis, muscle contraction, & cell signaling Endocrine diseases result from pathway or glandular hypo or hyper secretion