ENDOCRINE SYSTEM Chapter 16. ENDOCRINE GLANDS Ductless glands that produce hormones that are released directly into the bloodstream and are transported.

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<ul><li><p>ENDOCRINE SYSTEMChapter 16</p></li><li><p>ENDOCRINE GLANDSDuctless glands that produce hormones that are released directly into the bloodstream and are transported throughout the body to regulate the metabolic function of other cells in the body.Types of hormones:ParacrineAutocrine</p></li><li><p>Chemical Nature of HormonesAmino-acid based hormonesAmines=simple hormones derived from tyrosine (example: Epinephrine)Protein and peptides=chains of amino acids hooked together (example: ADH or Oxytocin)Steroid-based hormonesProgesteroneTestosteroneEicosanoids Hormone-like substances that act only on cells in the immediate vicinity (example: prostaglandin)</p></li><li><p>Functions of HormonesIntegrative</p><p>Homeostatic</p><p>Growth</p></li><li><p>Mechanisms of Hormone ActionLipid-soluble hormonesDiffusion occursBinds to intracellular receptorsForms hormone-receptor complexesHormone-receptor complex binds to specific receptor proteins on DNAInitiates transcription of certain genes</p></li><li><p>Mechanisms of Hormone ActionCyclic AMP signalingHormone binds to cell membrane receptorHormone-receptor complex binds to inactive G proteinG protein becomes active by GTP to GDPG protein binds adenylate cyclase producing Cyclic AMPCyclic AMP activates protein kinase enzymes</p></li><li><p>Mechanisms of Hormone ActionPIP-calcium signalingHormone binds to cell membrane receptorHormone-receptor complex binds to inactive G proteinG protein becomes active and binds to phospholipasePhospholipase splits to form IP3 and DAG which activate protein kinases and calcium</p></li><li><p>Control of HormonesFeedback MechanismsNegative feedbackPositive feedback</p><p>Responsiveness to target cellsConcentrations of hormonesNumber of receptorsInteraction of other hormones</p></li><li><p>Control of Hormones</p></li><li><p>Major Endocrine GlandsPituitary GlandThyroid GlandParathyroid GlandAdrenal GlandThymus GlandPineal GlandOther endocrine tissue</p></li><li><p>Pituitary Gland (Hypophysis)Posterior lobeOxytocinADHAnterior lobeGHTSHACTHFSHLHPRLMSH</p></li><li><p>Thyroid GlandFollicles and follicle cellsThyroglobulinColloidThyroxine (T4)Triiodothyronine (T3)Calorigenic effectCalcitonin produced by parafollicular cells</p></li><li><p>Parathyroid GlandProduces parathyroid hormone (PTH)Regulates calcium levels by targeting:BonesIntestineKidneys</p></li><li><p>Adrenal GlandAdrenal CortexZona glomerulosa produces mineralcorticoidsZona fasciculate produces glucocorticoidsZona reticularis produces androgens or adrenal sex hormones</p></li><li><p>Adrenal Gland (continued)Adrenal MedullaChromaffin cellsEpinephrineNorepinephrineAssociated with stress or Fight or Flight responses</p></li><li><p>Thymus and Pineal GlandThymus GlandThymosin stimulates T-cell maturationImmune system</p><p>Pineal GlandPinealocytesMelatonin</p></li><li><p>PancreasAlpha CellsProduce glucagonGlycogen&gt;&gt;Glugacon&gt;&gt;GlucoseBeta CellsProduce insulinEnhances uptake of glucose by cells as well as inhibits glycogenolysis and gluconeogenesisDelta CellsSomatostatinAcinar CellsProduces pancreatic enzymes but are exocrine</p></li><li><p>Pancreas (continued)</p></li><li><p>Other Endocrine TissuesOvaries=produce estrogen and progesteroneTestes=produce testosterone and inhibinPlacenta=produces HCGHeart=secretes ANPKidneys=secrete erythropoietinSkin=produces choleocalciferolAdipose tissue=releases leptinGastrointestinal tract=releases gastrin, secretin, serotonin, cholecystokinin and others</p></li><li><p>Homeostatic ImbalancesGigantismAcromegalyProgeriaPituitary dwarfismGalactorrheaGynecomastiaMyxedemaGoiterCretinism</p><p>Graves diseaseHyperparathyroidismHypoparathyroidismDiabetes insipidusDiabetes mellitusAldosteronismAddisons diseaseCushings diseaseMasculinization</p></li><li><p>Thyroid Gland (continued)</p></li><li><p>Thyroid Gland (continued)</p></li><li><p>Cushings Disease</p></li><li><p>Cushing Disease</p></li><li><p>Acromegaly</p></li><li><p>Gigantism and Pituitary Dwarfism</p></li><li><p>Addisons Disease</p></li></ul>

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