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THIRD EDITION HUMAN PHYSIOLOGY AN INTEGRATED APPROACH Dee Unglaub Silverthorn, Ph.D. Chapter 7 and 23 The Endocrine System PowerPoint® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Regulating Systems: Overview • Neurotransmitters: neuron to neuron communication across a synapse. • Hormones: cell to cell communication molecules • Made in gland(s) or cells • Transported by blood (humoral) over long distances. • Act by binding to receptors • Activates physiological response Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The pituitary is two fused glands Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neurohormones: secreted into the Blood by Neurons Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-12: Synthesis, storage, and release of posterior pituitary hormones Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hypothalamic-hypophyseal Portal system Anterior/Posterior pituitary gland secretions • Anterior Pituitary: 6 hormones • Prolactin • Growth hormone • Follicle stimulating hormone • Luteinizing hormone • Thyroid stimulating hormone • Adrenocorticotropic hormone • Posterior Pituitary: 2 hormones • Vasopressin • oxytocin Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Oxytocin vasopressin Prolactin Growth hormone TSH ACTH FSH LH Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hypothalamic hormones: control anterior pituitary • Dopamine / prolactin releasing hormone • Thyrotropin releasing hormone • Corticotropin-releasing hormone • Growth hormone-releasing hormone / growth hormone-inhibiting hormone • Gonadotropin-releasing hormone Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Terminology • Tropic hormone: • A hormone that controls the secretion of another hormone is known as a trophic (tropic) hormone. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Anterior pituitary: Three Levels of Integration Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-13: Hormones of the hypothalamic-anterior pituitary pathway Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Negative Feedback Controls: Long & Short Loop Reflexes Short Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings long Figure 7-14: Negative feedback loops in the hypothalamicanterior pituitary pathway Negative Feedback Controls: Long & Short Loop Reflexes Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-15: Control pathway for cortisol secretion Thyroid Thyroid hormones are not Essential for life but can Affect quality of life Increase oxygen consumption *Protein catabolism Nervous system development *increase activity in Na/K ATPase pumps Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid Gland: Hormones and Iodine Metabolism • C-cells – calcitonin • Follicle cells – thyroid hormones – T3, T4 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 Thyroid hormones are AMINES from tyrosine: Carry iodine. 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 T3 & T4 Control Pathways & Diseases from Malfunction Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-12: Thyroid hormone pathway Neurohormones: secreted into the Blood by Neurons • Adrenal Medulla–catecholamines; fight or flight • Mostly epinephrine Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sex hormones Glucocorticoids – cortisol Mineralcorticoids - aldosterone 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 Control of Cortisol Secretion: Feedback Loops • External stimuli • Hypothalamic • Anterior Pituitary • Adrenal cortex • Tissues Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-3: The control pathway for cortisol Bone remodeling BLOOD CALCIUM Osteoblast activity: Osteoclast activity: Bone deposition Bone resorption Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis • Excessive loss of calcium from bones. • When blood calcium is depleted, bones lose their mineral mass and progressively become porous. The bone matrix becomes weaker and increasingly vulnerable to fracture. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis; What Causes it? • 1. Lack of estrogen • Estrogen stimulates the osteoblasts to store calcium • This can be disrupted in overtraining/undereating female athletes • When body fat is very low or calorie intake is not high enough, females may cease menstruation. • 2. Dietary calcium deficiency • 3. Lack of regular exercise: weight bearing or resistance training makes bone respond! • 4. Excessive protein intake (in post-menopausal women) • Ammonium (NH3) waste from protein is buffered by calcium then excreted in the urine. • 5. Excessive alcohol intake: a diuretic that causes calcium to be excreted in the urine • 6. smoking: decreases activity of osteoblasts. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 3 hormones that control calcium balance • Parathyroid hormone (PTH) • Calcitriol • Calcitonin Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings • Stimulus for release is low calcium levels • PTH increases Ca++ levels • PTH mobilizes Ca++ from bone • Renal Ca++ absorption • Indirectly Ca++ intestinal absorption Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Calcitriol; reinforces plasma Ca++ increasing effects of PTH; made from vitamin D Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Calcitonin • Calcitonin is released when Ca++ goes up. • Opposite of PTH • Decreases bone resorption • Increases renal calcium excretion. • Released from C cells of the thyroid gland. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Calcium Metabolism: Figure 23-20: Calcium balance in the body Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings