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Essentials of Human Anatomy & Physiology Seventh Edition Elaine N. Marieb Chapter 9 The Endocrine System Slides 9.1 – 9.22 Lecture Slides in PowerPoint by Jerry L. Cook Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings I. The Endocrine System A. Uses chemical messages (hormones) that are released into the blood B. Hormones are produced by specialized cells C. Cells secrete hormones into extracellular fluids D. Blood transfers hormones to target sites Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.1 E. These hormones regulate the activity of other cells • Reproduction • • Gonads (testosterone/estrogen) Growth and development • • Pituitary (GH) Mobilization of body defenses • • Adrenaline rush (adrenal gland) Maintenance of much of homeostasis • • Ex—diabetes (can’t regulate blood sugar) Regulation of metabolism • Thyroid gland II. The Chemistry of Hormones A. Amino acid-based hormones Proteins Peptides Amines B. Steroids – made from cholesterol C. Prostaglandins – made from highly active lipids Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.3 III. Mechanisms of Hormone Action A. Hormones affect only certain tissues or organs (target cells or organs) B. Target cells must have specific protein receptors C. Hormone binding influences the working of the cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.4 D. Effects Caused by Hormones 1. Changes in plasma membrane permeability or electrical state 2. Synthesis of proteins, such as enzymes 3. Activation or inactivation of enzymes 4. Stimulation of mitosis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.5 E. Steroid Hormone Action 1. Steroid hormones can diffuse through the plasma membrane of target cells 2. Enter the nucleus 3. Bind to specific sites on the cell’s DNA 4. Activate genes that result in synthesis of new proteins Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.6 Steroid Hormone Action Figure 9.1a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.7 F. Non-steroid Hormone Action 1. Hormone binds to a membrane receptor 2. Hormone does not enter the cell 3. Sets off a series of reactions that activates an enzyme 4. Catalyzes a reaction that produces a second messenger molecule 5. Oversees additional intracellular changes to promote a specific response Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.8 Nonsteroid Hormone Action Figure 9.1b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.9 G. Control of Hormone Release 1. Hormone levels in the blood are maintained by negative feedback 2. A stimulus or low hormone levels in the blood triggers the release of more hormone 3. Hormone release stops once an appropriate level in the blood is reached Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.10 IV. Stimuli of Endocrine Glands A. Endocrine glands are activated by other hormones Figure 9.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.11 B. Changing blood levels of certain ions stimulate hormone release Figure 9.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.12 C. In some cases Nerve impulses stimulate hormone release D. Most are under control of the sympathetic nervous system Figure 9.2c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.13 Location of Major Endrocrine Organs Slide 9.15 Figure 9.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.14 V. Hormone-Producing Tissues and Organs A. Parts of the small intestine B. Parts of the stomach C. Kidneys D. Heart E. Many other areas have scattered endocrine cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.39 F. Endocrine Function of the Placenta 1. Produces hormones that maintain the pregnancy 2. Some hormones play a part in the delivery of the baby 3. Produces HCG in addition to estrogen, progesterone, and other hormones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.40 VI. Developmental Aspects of the Endocrine System A. Most endocrine organs operate smoothly until old age 1. Menopause is brought about by lack of efficiency of the ovaries 2. Problems associated with reduced estrogen are common 3.Growth hormone production declines with age 4. Many endocrine glands decrease output with age Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.41