Y khoa - Dược - Chapter 34: The endocrine system

34The Endocrine SystemLearning Outcomes (cont.)34.1 Describe the general functions of hormones and the endocrine system. 34.2 Identify the hormones released by the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, and other hormone-producing organs, and give the functions of each. Learning Outcomes (cont.)34.3 Explain the effect of stressors on the body. 34.4 Describe the causes, signs and symptoms, and treatments of various endocrine disorders. target tissuesIntroductionThe endocrine system includes the organs that secrete hormones Hormones Regulate chemical reactions in cells Control functions of the organs, tissues, and other cellsGlandssecretehormonesintobloodstreamtoHormones Endocrine glands DuctlessRelease hormones Directly into target tissuesInto bloodstream to be carried to target tissuesHormones – chemicals secreted by a cell that affect the functions of other cellsTypes of Hormones Steroidal HormonesCross cell membrane Bind to receptor in cell nucleusHormone-receptor complexesTurn a gene on or off Enable cell to carry out functionsTypes of Hormones (cont.)Nonsteroidal hormonesCannot cross the membrane Bind to receptors on the membraneHormone-receptor complexesActivate G-proteins which turn on enzymesCell takes on new functionsTypes of Hormones (cont.)ProstaglandinsDerived from lipid moleculesTarget cells are located close byProduced by organs such asKidneysHeartStomach UterusBrain Negative and Positive Feedback LoopsNegative feedback loop – hormone release stops in response to decrease in stimulusAs body cells take up blood glucose, glucoselevels in the blood decline, and insulin releasestops (negative feedback).Milk is released and thebaby continues to feedNegative and Positive Feedback LoopsPositive feedback loop – as long as stimulus is present, action of hormone continuesApply Your KnowledgeMatch the following:___ Chemicals that effect cell function A. Nonsteroidal hormone___ Easily cross cell membranes B. Steroidal hormone___ Made of amino acids C. G-protein___ Target nearby cells D. Prostaglandins___ Activated by hormone-receptor E. Hormones complex___ Cannot cross cell membranes easily___ Estrogen and cortisolBADCABEANSWER:VERY GOOD!Hormone ProductionHypothalamusHormonesOxytocinAntidiuretic hormone (ADH)Hormones transported to the posterior pituitary for storage Directs posterior pituitary to release hormones The Pituitary GlandControlled by the hypothalamusLocated at the base of the brain Two lobesAnterior lobePosterior lobeThe Pituitary Gland (cont.)Anterior lobeGrowth Hormone (GH)Increase in size of muscles and bonesRepair of tissuesMelanocyte-stimulating hormone (MSH)Synthesis of melaninDisbursement of melanin to skin cellsAdrenocorticotropic hormone (ACTH)Stimulates the adrenal cortex to release its hormonesThyroid-stimulating hormone (TSH)Stimulates the thyroid gland to release its hormonesThe Pituitary Gland (cont.)Anterior lobeFollicle-stimulating hormone (FSH)FemalesProduction of estrogenMaturation of ovaMales – sperm productionLuteinizing hormone (LH)Females OvulationProduction of estrogenMales – production of testosteroneProlactin (PRL)Females – milk production Males – enhances LHThe Pituitary Gland (cont.)Posterior lobeAntidiuretic hormone (ADH)Stimulates kidneys to conserve waterDecreases urine outputMaintains blood pressureOxytocin (OT)FemalesUterine contractions Ejection of milk Males – contraction of the prostate and vas deferensThe Thyroid Gland and Parathyroid GlandsThyroid GlandFollicles ~ store hormonesHormones Thyroid hormonesIncrease energy productionStimulate protein synthesisSpeed up repair of damaged tissuesCalcitonin – lowers blood calcium levels by activating osteoblastsThe Thyroid Gland and Parathyroid GlandsParathyroid glandsPosterior surface of thyroid glandSecrete parathyroid hormone (PTH) – An agonist to calcitoninRaises blood calcium levels by activating osteoclastsThe Adrenal GlandsAdrenal medullaCentral portionHormones produce same effects as the sympathetic nervous systemEpinephrine NorepinephrineThe Adrenal Glands (cont.)Adrenal cortexTwo main hormonesAldosteroneStimulates body to retain sodium Important in maintaining BPCortisol Released when stressedDecreases protein synthesis, resulting in slowed tissue repairDecreases inflammationThe PancreasHas both exocrine and endocrine functionsExocrine gland – secretes digestive enzymes into a duct leading to the small intestineEndocrine gland – secrete hormones into blood stream The Pancreas (cont.)Islets of Langerhans Cells with endocrine functionAlpha cells secrete glucagonBeta cells secrete insulin InsulinBlood glucose concentrationsProtein synthesisGlucagonProtein synthesisBlood glucose concentrationsOther Hormone-Producing Organs Pineal body – melatoninRegulates circadian rhythmsMay play a role in onset of pubertyThymus gland – thymosinOther Hormone-Producing Organs (cont.)The gonadsOvariesEstrogenProgesteroneTestes Testosterone Stomach – gastrinOther Hormone-Producing Organs (cont.)Small intestineSecretinCholecystokinin Heart – atrial natriuretic peptide ~ regulates blood pressureKidneys – erythropoietin ~ stimulates blood cell productionApply Your Knowledge1. Match the following: ___ Produces melatonin ___ Milk production ___ Maturation of ova and sperm production___ Sodium retention ___ Conservation of water___ Produces erythropoietin Increases cellular energy production Lowers blood calcium levels Released during stressEBCIADHANSWER:Follicle-stimulating hormoneADHProlactinThyroid hormoneKidneysCortisol Calcitonin Pineal bodyAldosterone GFApply Your Knowledge2. What are the effects of insulin and glucagon?ANSWER: Insulin decreases blood glucose concentration and increases protein synthesis.Glucagon does just the opposite. It increases blood glucose and decreases protein synthesis.Good Job!The Stress ResponseStressor Any stimulus that produces stressTypes Physical factors Psychological factorsPositive stimuliThe Stress Response (cont.)General stress syndromePhysiologic response to stress Caused by hormone releaseEffectsIncreased heart rate, respiratory rate, and BPIncrease in glucose and fatty acids in bloodIncrease in cortisolApply Your KnowledgeMatch the following:___ Extreme heat A. Physical stress___ Death of friend B. Psychological stress___ Fractured leg C. Positive stimulus___ Wedding___ Exam___ Hearing an explosion nearby___ “A” on an exam___ Flu___ Car stolenBBBAACBCAANSWER: Disease/DisorderDescriptionAcromegalyEnlargement of bones and thickened skinCauses: Too much growth hormone produced in adults; tumor of pituitaryAddison’s diseaseAdrenal gland fails to produce enough corticosteroidsCause is unknown – possibly an autoimmune dysfunction; cancerCommon Diseases and Disorders of the Endocrine SystemCommon Diseases and Disorders of the Endocrine System (cont.)Disease/DisorderDescriptionCushing’s diseaseMoon face, buffalo hump, thin arms and legs; large abdomenHypercortisolismCauses: excessive production of ACTH; tumor of the adrenal gland or pituitary gland; long term use of steroidsDiabetes insipidusKidneys fail to reabsorb water, resulting in excessive urinationCause: hyposecretion of ADHCommon Diseases and Disorders of the Endocrine System (cont.)Disease/DisorderDescriptionDiabetes mellitusType IType IIGestationalChronic disease characterized by elevated blood glucose levelsInsulin-dependent diabetes mellitus; usually develops in childhoodNoninsulin-dependent diabetes mellitus; primarily in adults but increased incidence in teens Occurs during pregnancy; usually temporaryCommon Diseases and Disorders of the Endocrine System (cont.)Disease/DisorderDescriptionDwarfismShort height, abnormal facial features, cleft lip or palate, delayed pubertyCauses: Too little growth hormone produced during childhood; trauma to or tumor of the pituitary glandCommon Diseases and Disorders of the Endocrine System (cont.)Disease/DisorderDescriptionGigantismVery tall, delayed sexual maturity, thick facial bonesCauses: Too much growth hormone produced during childhood; pituitary gland tumorGoiterEnlargement of thyroid gland, causing swelling in neckCause: deficiency of iodine in dietCommon Diseases and Disorders of the Endocrine System (cont.)Disease/DisorderDescriptionGraves’ diseaseHyperthyroidismExophthalmos; goiterCauses: antibodies attack the thyroid gland, causing it to produce too much thyroid hormone; autoimmune disorderCommon Diseases and Disorders (cont.)Disease/DisorderDescriptionCretinismSevere hypothyroidism present prior to or soon after birthCauses: absence or malformation of thyroid gland; abnormal formation of thyroid hormones; pituitary failureMyxedemaSevere form of hypothyroidismCauses: removal of thyroid gland; radiation treatments to neck; obesity; may be congenitalApply Your KnowledgeTrue or False:___ Acromegaly develops as a result of too much growth hormone in a  child.___ In diabetes insipidus, the kidneys fail to reabsorb water.___ Too little growth hormone in childhood results in dwarfism.___ Myxedema is the result of hyperthyroidism.___ Addison’s disease is the result of too little corticosteroid.___ Cushing’s disease is the result of too little ACTH.___ Cretinism is an extreme form of hyperthyroidism present at birth.FTTTFFANSWER:Fhypothyroidismtoo much ACTHhypothyroidismin an adultCorrect!In Summary34.1 Endocrine glands are ductless glands, releasing hormones directly into the bloodstream and tissues. The organs of the endocrine system produce hormones that regulate the chemical reactions within cells, controlling the functions of organs, tissues, and other cells. Hormone levels are controlled by positive and negative feedback loops. In Summary (cont.)34.2 The pituitary gland releases: GH, MSH, ACTH, TSH, FSH, LH, PRL, ADH, and OT. The thyroid gland releases calcitonin, T 3, and T 4. The parathyroid gland releases PTH. The adrenal medulla secretes epinephrine and norepinephrine. The adrenal cortex produces aldosterone and cortisol. The hormone- releasing of cells in the pancreas release glucagon and insulin. The pineal body releases melatonin; the thymus releases thymosin and thymopoietin; ovaries release estrogen and progesterone (females); and the testes (males) release testosterone. The kidneys produce erythropoietin, and the heart produces atrial natriuretic peptide. In Summary (cont.)34.3 Stressors are stimuli that produce a stress response, a physiologic response to the stimulus that changes the body’s functioning in some way. 34.4 The diseases and disorders of the endocrine system are as varied as the organs and hormone dysfunctions that cause them. An overview of these conditions is found in Table 34-2. End of Chapter 34Its not stress that kills us, it is our reaction to it. ~ Hans Selye