2/28/18 Introduction • Endocrine system works with nervous system to coordinate body functions - Nervous system uses impulses and Endocrine System neurotransmitters - Endocrine system uses hormones • Many cells have receptors for both Chapter 24 neurotransmitters and hormones and can be regulated by both chemicals Copyright © 2016 by Elsevier Inc. All rights reserved. 1 Copyright © 2016 by Elsevier Inc. All rights reserved. 2 Comparing Endocrine and Introduction Nervous System Functions • Exocrine glands: Secrete products into ducts that open into body cavities - Sudoriferous: Secrete sweat - Sebaceous: Secrete oil - Ceruminous: Secrete ear wax • Endocrine glands - Secrete hormones directly into bloodstream - Ductless glands Copyright © 2016 by Elsevier Inc. All rights reserved. 3 Copyright © 2016 by Elsevier Inc. All rights reserved. 4 Major Endocrine Glands Anatomy • Hypothalamus • Pituitary • Pineal • Thyroid • Parathyroids • Adrenals • Pancreatic islets • Ovaries • Testes • Hormones From Koeppen BM: Berne & Levy Physiology, Updated Edition, ed 6, St. Louis, 2010, Mosby. Copyright © 2016 by Elsevier Inc. All rights reserved. 5 Copyright © 2016 by Elsevier Inc. All rights reserved. 6 1 2/28/18 Physiology Hormones and Regulation • Hormone production and secretion • Chemical messengers that regulate the • Regulation of metabolism physiologic activity of other cells • Stress adaptation • Have potential to come in contact with every • Chemical composition and fluid volume cell type regulation - Target cells are chemically compatible with • Reproductive process regulation corresponding hormone(s) - Lock together with receptor sites Copyright © 2016 by Elsevier Inc. All rights reserved. 7 Copyright © 2016 by Elsevier Inc. All rights reserved. 8 Hormonal Control Mechanisms Negative Feedback Regulation • Types are: • Movement reverses deviations from - Negative feedback regulation homeostasis - Hormonal regulation • Glands respond to information - Neural regulation - Secrete more or less hormone • Positive feedback systems also regulate hormones Copyright © 2016 by Elsevier Inc. All rights reserved. 9 Copyright © 2016 by Elsevier Inc. All rights reserved. 10 Hormonal Regulation Neural Regulation • Hormone from one endocrine gland binds to • Neural impulses stimulate release of receptor sites on another endocrine gland hormones • Tropic hormones stimulate other endocrine • Epinephrine and norepinephrine maintain glands fight-or-flight response - Most are secreted by anterior pituitary • These systems have a faster response than other regulation systems Copyright © 2016 by Elsevier Inc. All rights reserved. 11 Copyright © 2016 by Elsevier Inc. All rights reserved. 12 2 2/28/18 Hypothalamus Hypothalamic Hormones • Regulates the autonomic nervous system and • Stimulatory controls many behaviors - Thyrotropin-releasing hormone, gonadotropin- • Links nervous system to endocrine system releasing hormone, growth hormone-releasing through pituitary gland hormone, prolactin-releasing hormone, and corticotropin-releasing hormone • Stimulates or inhibits pituitary hormones • Inhibitory - Growth hormone-inhibiting hormone - Prolactin-inhibiting hormone Copyright © 2016 by Elsevier Inc. All rights reserved. 13 Copyright © 2016 by Elsevier Inc. All rights reserved. 14 Pituitary Pituitary Hormones • Lies in sella turcica of sphenoid bone • Consists of: - Anterior lobe: Constitutes 75% of entire gland - Posterior lobe: Regulated by the nervous system Copyright © 2016 by Elsevier Inc. All rights reserved. 15 Copyright © 2016 by Elsevier Inc. All rights reserved. 16 Anterior Pituitary Hormones Anterior Pituitary Hormones • Adrenocorticotropic hormone (ACTH) • Luteinizing hormone (LH) - Stimulates hormones of adrenal cortex, especially - Women: Stimulates estrogens and progesterone, cortisol ovulation, and corpus luteum development • Growth hormone (GH) - Men: Stimulates testosterone production - Stimulates protein synthesis for muscle and bone growth maintenance, repair, and metabolism • Prolactin (PRL) - Promotes milK production in the breasts • Thyroid-stimulating hormone (TSH) - Stimulates secretion of thyroid hormones • Melanocyte-stimulating hormone (MSH) • Follicle-stimulating hormone (FSH) - Increases sKin pigmentation - Women: Stimulates estrogen production and development of ovarian follicle - Men: Stimulates sperm production in the testes Copyright © 2016 by Elsevier Inc. All rights reserved. 17 Copyright © 2016 by Elsevier Inc. All rights reserved. 18 3 2/28/18 Posterior Pituitary Hormones Pineal Gland • Antidiuretic hormone (ADH) • Located posterior aspect of the diencephalon - Decreases urine production • Pine nut-shaped - Raises blood pressure by vasoconstriction • Chief hormone secreted is melatonin • Oxytocin (OT) - Controls biorhythms - Stimulates uterine contraction - Levels remain elevated for 12 hours - Stimulates milk expression Copyright © 2016 by Elsevier Inc. All rights reserved. 19 Copyright © 2016 by Elsevier Inc. All rights reserved. 20 Thyroid Thyroid Hormones • Located below the larynx and around the • Triiodothyronine (T3) and thyroxine (T4) front and sides of the trachea - Collectively called thyroid hormones (TH) • Contains two lobes connected at center by - Regulates metabolism the isthmus - Affect growth and development - Cannot be made without iodine - Occasionally, a third lobe will arise Copyright © 2016 by Elsevier Inc. All rights reserved. 21 Copyright © 2016 by Elsevier Inc. All rights reserved. 22 Thyroid Hormones Thyroid and Parathyroid Glands • Calcitonin (CT) - Decreases blood calcium levels (hypocalcemic) by stimulating osteoblast activity - Decreases with advancing age From Christensen BL: Adult Health Nursing, ed 6, St. Louis, 2010, Mosby. Copyright © 2016 by Elsevier Inc. All rights reserved. 23 Copyright © 2016 by Elsevier Inc. All rights reserved. 24 4 2/28/18 Parathyroid Adrenals • Located on posterolateral surface of thyroid • Cortex is outer region lobes - Produces three steroid hormones: • Mineralocorticoids • Usually four in number • Glucocorticoids • Parathyroid hormone (PTH) • Sex hormones (adrenal estrogens and adrenal - Increases blood calcium levels (hypercalcemic) by androgens) stimulating osteoclastic activity • Medulla is the inner region - Increases calcium absorption in intestines - Produces epinephrine and norepinephrine Copyright © 2016 by Elsevier Inc. All rights reserved. 25 Copyright © 2016 by Elsevier Inc. All rights reserved. 26 Adrenal Cortex and Adrenal Glands Adrenal Medulla Hormones • Cortisol (Hydrocortisone) - Influences the metabolism of food molecules, such as carbohydrates, proteins, and fats - Has antiinflammatory effect in large amounts • Aldosterone maintains sodium levels in the blood • Epinephrine or adrenaline and norepinephrine or noradrenaline bind to receptors of sympathetic effectors Copyright © 2016 by Elsevier Inc. All rights reserved. 27 Copyright © 2016 by Elsevier Inc. All rights reserved. 28 Pancreatic Islets Pancreatic Hormones • Also called islets of Langerhans • Insulin • Contains: - Decreases blood glucose levels by moving - Alpha cells: Secrete glucagon glucose into cells - Beta cells: Secrete insulin - Secreted by pancreatic beta cells - Delta cells: Secrete somatostatin and pancreatic - Cannot be given orally polypeptides Copyright © 2016 by Elsevier Inc. All rights reserved. 29 Copyright © 2016 by Elsevier Inc. All rights reserved. 30 5 2/28/18 Regulation of Blood Pancreatic Hormones Glucose by Pancreas • Glucagon - Increases blood glucose levels by moving stored glucose to the blood - Secreted by pancreatic alpha cells From Goodman CC: Pathology for the Physical Therapy Assistant, ed 1, St. Louis, 2011, Saunders. Copyright © 2016 by Elsevier Inc. All rights reserved. 31 Copyright © 2016 by Elsevier Inc. All rights reserved. 32 Ovaries Ovarian Hormones • Located in female abdominopelvic area • Estrogens • Secrete estrogens and progesterone - Responsible for secondary sex characteristics in • Regulate menstrual cycle and secondary sex females characteristics - Promote the proper sequence of events of the menstrual cycle • Other hormones are relaxin and inhibin • Progesterone - Maintains uterine lining for implantation and gestation - Slightly elevates temperature for incubating effect Copyright © 2016 by Elsevier Inc. All rights reserved. 33 Copyright © 2016 by Elsevier Inc. All rights reserved. 34 Testes Testicular Hormones • Located in male scrotum • Testosterone • Contains interstitial cells of Leydig - Stimulates sperm production - Produce androgens - Responsible for secondary sex characteristics in • Principal androgen is testosterone males - Involved in increasing libido Copyright © 2016 by Elsevier Inc. All rights reserved. 35 Copyright © 2016 by Elsevier Inc. All rights reserved. 36 6 2/28/18 Organs That Possess Endocrine Cells Thymus: Hormones • Kidneys • Thymosin And thymopoietin • Hormones - StimulAtes T-cell maturation - Erythropoietin - Involved in immune responses • Secreted when blood oxygen levels decline • Stimulates production of additional red blood cells in bone marrow - Renin • Secreted when blood pressure in kidneys drops below a certain level • Stimulates a negative feedback system called the renin- angiotensin-aldosterone system, which increases blood pressure Copyright © 2016 by Elsevier Inc. All rights reserved. 37 Copyright © 2016 by Elsevier Inc. All rights reserved. 38 Gastric and Intestinal Placenta: Hormones Mucosa: Hormones • Human chorionic gonadotropin (HCG) • Gastrin - Pregnancy hormone, present in blood