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Anatomy and Physiology
D- Chapter 13 Lecture PowerPoint Endocrine Anatomy and Physiology Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Chapter 13 Endocrine System
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13.1: Introduction The endocrine system assists the nervous system with communication and control of the body The cells, tissues, and organs are called endocrine glands They are ductless They use the bloodstream They secrete hormones There are also similar glands called paracrine and autocrine glands that are quasi-endocrine Other glands that secrete substances are the exocrine glands They have ducts They deliver their products directly to a specific site 3
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4 Thyroid gland Endocrine gland Hormone secretion Endocrine cell
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thyroid gland Endocrine gland Hormone secretion Endocrine cell Blood flow (a) Skin Duct Exocrine gland (sweat gland) Exocrine cells 4 (b)
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13.2: General Characteristics of the Endocrine System
The endocrine and nervous systems communicate using chemical signals Neurons release neurotransmitters into a synapse affecting postsynaptic cells Endocrine glands release hormones into the bloodstream to specific target cell receptors 5
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Nerve impulse Neuron transmits nerve impulse Neurotransmitter
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nerve impulse Neuron transmits nerve impulse Neurotransmitter released into synapse Post- synaptic cell responds (a) Target cells (cells with hormone receptors) respond to hormone Glandular cells secrete hormone into bloodstream Bloodstream Hormones have no effect on other cells (b) 6
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13.3: Hormone Action Hormones are released into the extracellular spaces surrounding endocrine cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hypothalamus Pineal gland Pituitary gland Parathyroid gland Thyroid gland Thymus Adrenal gland Kidney Pancreas Ovary (in female) Testis (in male) 8
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Chemistry of Hormones Chemically, hormones are either:
Steroid or steroid-like hormones such as: Sex hormones Adrenal cortex hormones Non-steroid hormones such as: Amines Proteins Peptides Glycoproteins 9
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10 CH2OH C O H3C HO OH OH H H3C HO C C NH2 HO H H O (a) Cortisol
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CH2OH C O H3C HO OH OH H H3C HO C C NH2 HO H H O (a) Cortisol (b) Norepinephrine Ala Val Ser Glu Glu Phe Ile Gly Asp Lys His His Ser Leu Leu Met Glu Gly Ser Asp Leu Glu Glu Lys Lys Lys Ala Ala Pro Pro Glu Glu Lys Val Val Asp His Lys Lys Ser Arg Gly Arg Arg Asp Ser Glu Pro Arg Asp Ala Ala Val Leu Glu Lys Tyr Asp Leu Leu Leu Ile Val Val Asp Ser Lys Gly Glu Arg Lys Lys Gly Try His Ileu Met Glu Ser Phe Ala Val Leu Glu (c) Parathyroid ho rm one (PTH) O H H H H H H H C O Tyr Cys C C C C C C C C Ile H OH S H H H H C H H H H H H S H Glu C C C C C C C C C H Cys Pro Leu Gly Asp C H H H OH H 10 H H H H H OH (d) Oxytocin (e) Prostaglandin PGE2
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Action of Hormones Steroid Hormones 13 Hormone molecule Cell membrane
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Steroid Hormones Hormone molecule Cell membrane 1 Newly forming protein molecule Ribosome mRNA 5 Nucleus 4 mRNA Intracellular receptor molecule 2 Hormone-receptor complex DNA 3 13
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Action of Hormones Non-steroid Hormones 14 Cell membrane
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Non-steroid Hormones Cell membrane Membrane-bound receptor molecule Nonsteroid hormone molecule 1 2 Hormone- receptor complex G protein Adenylate cyclase 3 4 ATP Protein kinases (inactive) cAMP 5 Cytoplasm Protein kinases (active) Substrate (inactive) Substrate (active) Cellular changes Nucleus 14
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Using Hormones to Improve
13.1 Clinical Application Using Hormones to Improve Athletic Performance 15
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Prostaglandins Prostaglandins: Are paracrine substances
Are very potent in small amounts Are not stored in cells but synthesized just before release Rapidly inactivate Regulate cellular responses to hormones Can activate or inhibit adenylate cyclase Controls cAMP production Alters a cells response to hormones Has a wide variety of effects 16
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13.4: Control of Hormonal Secretions
Primarily controlled by negative feedback mechanism Hormones can be short-lived or may last for days Hormone secretions are precisely regulated 17
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Control Sources 18 Control center Endocrine gland inhibited. Receptors
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center Endocrine gland inhibited. Receptors Hormone control mechanism senses change. Effectors Hormone secretion decreased. Stimulus Hormone levels rise or controlled process increases. Response Hormone levels return toward normal. too high Normal hormone levels too low Stimulus Hormone levels drop or controlled process decreases. Response Hormone levels return toward normal. Receptors Hormone control mechanism senses change. Effectors Hormone secretion increased. 18 Control center Endocrine gland stimulated.
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Control Sources – – – – 19 Hypothalamus Nervous system Changing level
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Hypothalamus – Nervous system – Changing level of substance in plasma – Anterior pituitary gland Peripheral endocrine gland Endocrine gland Endocrine gland Target cells Target cells Target cells Action Action Action (a) (b) (c) 19
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13.5: Pituitary Gland Lies at the base of the brain in the sella turcica Consists of two distinct portions: Anterior pituitary (adenohypophysis) Posterior pituitary (neurohypophysis) 20
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21 Third ventricle Hypothalamus Anterior cerebral artery Optic chiasma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Third ventricle Hypothalamus Anterior cerebral artery Optic chiasma Optic nerve Oculomotor nerve Pituitary stalk (Infundibulum) Trochlear nerve Posterior lobe of pituitary gland Anterior lobe of pituitary gland Sella turcica Sphenoidal sinus Basilar artery Sphenoid bone 21
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Anterior Pituitary Hormones
Hypothalamic releasing hormones stimulate cells of anterior pituitary to release hormones Nerve impulses from hypothalamus stimulate nerve endings in the posterior pituitary gland to release hormones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Third ventricle Optic chiasma Neurosecretory cells that secrete posterior pituitary hormones Neurosecretory cells that secrete releasing hormones Hypothalamus Hypophyseal portal veins Superior hypophyseal artery Secretory cells of anterior pituitary gland Capillary bed Inferior hypophyseal artery Capillary bed Hypophyseal veins Sella turcica of sphenoid bone 22 Anterior lobe of pituitary gland Posterior lobe of pituitary gland
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© Michael Ross/Photo Researchers, Inc.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Hypothalamus – Secretory cells Releasing hormone (Hormone 1) + – Anterior pituitary Anterior pituitary hormone (Hormone 2) + © Michael Ross/Photo Researchers, Inc. Peripheral endocrine gland (Hormone 3) Stimulation + Inhibition Target cells 23
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24 Hormones from Hypothalamus GHRH Growth hormone- releasing hormone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hormones from Hypothalamus GHRH Growth hormone- releasing hormone SS Somatostatin PRF Prolactin- releasing factor PIH Prolactin- release inhibiting hormone TRH Thyrotropin- releasing hormone CRH Corticotropin- releasing hormone GnRH Gonadotropin- releasing hormone Hormones from Anterior Pituitary GH Growth hormone PRL Prolactin TSH Thyroid- stimulating hormone ACTH Adrenocorticotropic hormone LH Luteinizing hormone FSH Follicle- stimulating hormone Bone Muscle Adipose tissue Mammary gland Thyroid Adrenal cortex Ovary Testis 24
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Growth Hormone Ups and Downs
13.2 Clinical Application Growth Hormone Ups and Downs 25
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Posterior Pituitary Hormones
Structurally consists of nerve fibers and neuroglia v. glandular epithelial cells of the anterior pituitary gland The nerve fibers originate in the hypothalamus Two hormones are produced: Antidiuretic hormone (vasopressin) Oxytocin 26
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13.6: Thyroid Gland The thyroid gland has two lateral lobes and lies just below the larynx It produces three hormones: T3 (thyroxine) T4 (triiodothyronine) Calcitonin 28
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© Fred Hossler/Visuals Unlimited
Structure of the Gland Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Larynx Colloid Thyroid gland Follicular cell Follicular cells Colloid Isthmus Extrafollicular cell (a) (b) Extrafollicular cells © Fred Hossler/Visuals Unlimited 29
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Thyroid Hormones 30 OH OH I I I O O I I I I CH2 CH2 NH2CHCOOH
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. OH OH I I I O O I I I I CH2 CH2 NH2CHCOOH NH2CHCOOH Thyroxine (T4) Triiodothyronine (T3) 30
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Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Mediscan/Visuals Unlimited © Mediscan/Visuals Unlimited © Mediscan/Visuals Unlimited 31
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13.7: Parathyroid Glands The parathyroid glands are on the posterior surface of the thyroid gland There are typically four parathyroid glands It secretes one hormone: PTH (parathyroid hormone or parathormone) 32
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Structure of the Glands
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Secretory cells Pharynx Thyroid gland Capillaries Parathyroid glands © R. Calentine/Visuals Unlimited Esophagus Trachea 33 Posterior view
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Controls absorption of
Parathyroid Hormone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Foods Cholesterol Intestinal enzymes Provitamin D Ultraviolet light in skin Vitamin D (Cholecalciferol) Also obtained directly from foods Liver Hydroxycholecalciferol Kidney Stimulated by PTH Dihydroxycholecalciferol (active form of vitamin D) Controls absorption of calcium in intestine Ca+2 34 Ca+2 Ca+2
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– + + 35 Parathyroid glands (on posterior of thyroid gland)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parathyroid glands (on posterior of thyroid gland) Release into bloodstream Decreased blood calcium stimulates parathyroid hormone secretion Increased blood calcium inhibits PTH secretion Stimulation – Inhibition PTH Bloodstream PTH PTH Ca+2 Ca+2 Ca+2 + + Bone releases Ca+2 Kidneys conserve Ca+2 and activate Vitamin D Intestine absorbs Ca+2 Active Vitamin D 35
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13.8: Adrenal Glands The adrenal glands are closely associated with the kidneys The gland sits like a cap on each kidney Hormones are secreted from two different areas of the gland, the adrenal cortex and the adrenal medulla Numerous hormones are secreted by the adrenal glands 37
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Structure of the Glands
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capsule Surface of adrenal gland Zona glomerulosa Connective tissue capsule Adrenal gland Zona lomerulosa Kidney Zona fasciculata Cortex Zona fasciculata Adrenal cortex Adrenal cortex Adrenal medulla Zona reticularis Zona reticularis (a) Adrenal medulla (b) Medulla Chromaffin cells © Ed Reschke 38
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Hormones of the Adrenal Medulla
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Hormones of the Adrenal Cortex
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Disorders of the Adrenal Cortex
13.3 Clinical Application Disorders of the Adrenal Cortex 41
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13.1 From Science to Technology
Treating Diabetes 42
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13.9: Pancreas The pancreas has two major types of secretory tissue
This is why it is a dual functioning organ as both an exocrine gland and endocrine gland Three hormones are secreted from the islet cells: Alpha cells secrete glucagon Beta cells insulin Delta cells secrete somatostatin 43
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Structure of the Gland 44 Pancreatic islet (Islet of Langerhans)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pancreatic islet (Islet of Langerhans) Gallbladder Common bile duct Pancreatic duct Duct Pancreas Small intestine Digestive enzyme- secreting cells Pancreatic islet (Islet of Langerhans) Capillary Hormone-secreting islet cells From Kent M. Van De Graaff and Stuart Ira Fox, Concepts of Human Anatomy and Physiology, 2nd ed. ©1989 Wm. C. Brown Publishers, Dubuque, Iowa. All Rights Reserved. Reprinted with permission 44
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Hormones of the Pancreatic Islets
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46 Control center Beta cells secrete insulin Effectors Insulin
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center Beta cells secrete insulin Effectors Insulin • Promotes movement of glucose into certain cells • Stimulates formation of glycogen from glucose Receptors Beta cells detect a rise in blood glucose Stimulus Rise in blood glucose Response Blood glucose drops toward normal (and inhibits insulin secretion) too high Normal blood glucose concentration too low Response Blood glucose rises toward normal (and inhibits glucagon secretion) Stimulus Drop in blood glucose Receptors Alpha cells detect a drop in blood glucose Effectors Glucagon • Stimulates cells to break down glycogen into glucose • Stimulates cells to convert noncarbohydrates into glucose Control center Alpha cells secrete glucagon 46
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13.4 Clinical Application Diabetes Mellitus 47
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13.10: Other Endocrine Glands
Pineal Gland Secretes melatonin Regulates circadian rhythms Thymus Gland Secretes thymosins Promotes development of certain lymphocytes Important in role of immunity Reproductive Organs Ovaries produce estrogens and progesterone Testes produce testosterone Placenta produces estrogens, progesterone, and gonadotropin Other organs: digestive glands, heart, and kidney 48
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13.11: Stress and Its Effects
Survival depends on maintaining homeostasis Factors that change the internal environment are potentially life-threatening Sensing such dangers directs nerve impulses to the hypothalamus This can trigger a loss of homeostasis 49
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Types of Stress Two types of stress: Physical stress
Psychological stress 50
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Responses to Stress 51 Stress results from changes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stress results from changes in the external environment Hormonal signals Neural signals Signals from sensory receptors Sympathetic impulses Hypothalamus CRH released Adrenal medulla Anterior pituitary Epinephrine and norepinephrine released Norepinephrine released ACTH released Adrenal cortex Short-term “fight or flight” or alarm stage. Cortisol released • Blood glucose increases. • Blood glycerol and fatty acids increase. Long-term adjustment or resistance stage • Heart rate increases. • Blood pressure rises. • Increase in blood concentration of amino acids. • Breathing rate increases. • Increased release of fatty acids. • Air passages dilate. • Increased glucose formed from noncarbohydrates—amino acids (from proteins) and glycerol (from fats). 51 • Pupils dilate. • Blood flow redistributes.
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13.12: Lifespan Changes Endocrine glands decrease in size
Muscular strength decreases as GH levels decrease ADH levels increase due to slower break down in liver and kidneys Calcitonin levels decrease; increase risk of osteoporosis PTH level changes contribute to risk of osteoporosis Insulin resistance may develop Changes in melatonin secretion affect the body clock Thymosin production declines increasing risk of infections 53
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Important Points in Chapter 13: Outcomes to be Assessed
13.1: Introduction Define hormone. Distinguish between endocrine and exocrine glands. 13.2: General Characteristics of the Endocrine System Explain what makes a cell a target cell for a hormone. List some important functions of hormones. 13.3: Hormone Action Describe how hormones can be classified according to their chemical composition. Explain how steroid and non-steroid hormones affect their target cells. 54
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Important Points in Chapter 13: Outcomes to be Assessed
13.4: Control of Hormone Secretion Discuss how negative feedback mechanisms regulate hormone secretion. Explain how the nervous system controls hormone secretion. : Pituitary Gland – Other Endocrine Glands Name and describe the locations of the major endocrine glands and list the hormones that they secrete. Describe the actions of the various hormones and their contributions to homeostasis. Explain how the secretion of each hormone is regulated. 55
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Important Points in Chapter 13: Outcomes to be Assessed
13.11: Stress and Its Effects Distinguish between physical and psychological stress. Describe the general stress response. 13.12: Lifespan Changes Describe some of the changes associated with aging of the endocrine system. 56
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