Endocrine system Chapter 45. Endocrine system Regulation & communication Blood system Glands (ductless) Hormones (chemicals) Target tissues.

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  • Endocrine systemChapter 45

  • Endocrine systemRegulation & communicationBlood system Glands (ductless)Hormones (chemicals)Target tissues

  • BloodvesselResponse(a) Endocrine signaling

  • Nervous systemRegulation & communicationNervesAxonNeurotransmittersSynapse

  • Both systems (overlap)NeurohormoneReleased by the nervous system Into blood stream (ADH)

    Norepinephrine Chemical involved in bothNervous system (cleft) Endocrine system (adrenal gland)

  • Both systemsNeural control of endocrine systemHypothalamus Regulates hormonal secretion of the anterior pituitaryGlands derived from nervous tissueAdrenal medulla, posterior pituitary & pineal gland

  • Local regulatorsParacrineMessages between neighboring cells1. Cytokines Regulate immune system2. Growth factorsRegulate cell growth3. NOVasodilation (local blood vessels)

  • Local regulators4. Prostaglandins20-carbon fatty acidDerived from lipids in plasma membraneFound in many organsReleased into interstitial fluid

  • Local regulators4. ProstaglandinsA. Immune system inflammationB. Reproductive systemLaborSemen C. Digestive systemInhibit gastric secretionsIncrease gut motility

  • Local regulatorsD. Respiratory systemSome cause dilationSome cause constrictionE. Circulatory systemPlatelets F. Urinary systemRenal vasodilationIncreased excretion

  • Hormone types1. PolypeptideShort, 100 aa, carbohydrate attached, FSH, LH3. AminesTyrosine & tryptophanAdrenal medulla (NE, Epinephrine)Thyroid (T3 & T4Pineal (Melatonin)

  • Hormone types4. SteroidsLipids from cholesterolTestosteroneEstradiol, progesteroneAldosterone, cortisol

  • Mechanism of regulation 1. Enter the cell LipophilicLipid soluble2. Do not enter the cell LipophobicWater soluble

  • Mechanism of regulation1. Lipophilic (Steroids, thyroxine)Not water solublePlasma attached to protein carriers Target cell-release carrierCross plasma membraneBind receptor protein (+/- nucleus)Hormone receptor binds DNAProtein synthesis

  • Mechanism of regulationE:\Chapter_45\A_PowerPoint_Lectures\45_Lecture_Presentation\45_05bLipidSolubleHormone_A.html

  • Mechanism of regulation2. Lipophobic or too largeBind receptors on target cell membraneA. Triggers second-messenger systemcAMP IP3/Ca+2B. Causes change in an ion channel

  • Mechanism of regulationE:\Chapter_45\A_PowerPoint_Lectures\45_Lecture_Presentation\45_05aWaterSolubleHormone_A.html

  • Mechanism of regulation

  • Mechanism of regulation

  • Mechanism of regulation

  • ThyroidNeck2 lobes/isthmusT4 (tetraiodothyronine) thyroxineT3 (triiodothyronine)Regulates metabolism in the bodyCalcitoninStimulates Ca2+ uptake into bonesDecreases serum Ca+2

  • Thyroid

  • Parathyroid glandsNeck 4 small glands on top of thyroidPTH (parathyroid hormone)Increase in blood calcium levelsStimulates osteoclasts Break down calcium phosphate crystalsStimulates kidneys to reabsorb Ca2+Activates Vitamin D

  • Parathyroid glands

  • PancreasAbdomen behind stomachIslets of Langerhans Insulin ( cells)Decreases blood glucose levelsStores in glycogen (liver/muscle) & fat (adipose cells)Glucagon ( cells)Increases glucose blood levels

  • Pancreas

  • Ovaries AbdomenEstrogenSecondary female characteristicsMenstruation ProgesteronePrepares/maintains pregnancy

  • TestesInguinal regionTestosteroneMaintain male characteristics

  • Ovaries and Testes

  • Steroids

  • Adrenal glandsSmall glands on top of kidneys1. Adrenal cortexOuter layer2. Adrenal medullaInner layer

  • Adrenal glandsAdrenal cortexA. CorticosteriodsCortisol (glucocorticoid)Increases serum levels of glucoseGluconeogenesis Converts aa to glucoseExercise or fasting

  • Adrenal glandsB. Mineralcorticoids AldosteroneStimulates kidneys to reabsorb Na+1Stimulates kidneys to eliminate K+1C. GonadocorticoidsAndrogensSex characteristics

  • Adrenal glandsAdrenal medullaCatacholaminesEpinephrine/norepinephrine Increased heart rate, BP, glucose blood levels, Dilation of bronchiolesDecreased blood flow to skin and gut

  • Adrenal glands

  • Pituitary gland (hypophysis)In the brain Hangs by a stalk from hypothalamus1.Anterior AdenohypophysisDeveloped from epithelial tissue2. Posterior NeurohypophysisDeveloped from the neural tissue Nerve axons from hypothalamus end here

  • Pituitary gland

  • Anterior pituitary glandAll hormones stimulate growth in target organsTropins A. GH (growth hormone)Somatotropin Stimulates muscle growth (bone)

  • Anterior pituitary glandB. ACTHAdrenocorticotropic hormoneCorticotropinStimulates adrenal cortex (cortisol)C. TSHThyroid-stimulating hormoneThyrotropin Stimulates thryroid to produce thyroxine

  • Anterior pituitary glandD. LHLuteinizing hormoneStimulates ovulation & lining of uterusStimulates testes to produce testosterone

  • Anterior pituitary glandE. FSHFollicle stimulating hormoneStimulates the egg developmentDevelopment of spermF. Prolactin Stimulates mammary glands to produce milk

  • LH, FSH

  • Anterior pituitary glandG. MSHMelanocyte-stimulating hormoneCauses darkening of skin in some fish, amphibians & reptiles

  • Posterior pituitary glandA. ADHAntidiuretic hormone (vasopressin) Stimulates water retention in the kidneysB. OxytocinMilk ejection from mammary glandsStimulates uterine contractions in labor

  • Pituitary gland

  • Pineal glandSmall mass of tissue located near center of brainSynthesizes & secretes melatonin (modified aa)Regulates functions related to day and night Seasons

  • HypothalamusSpinal cordPosteriorpituitaryCerebellumPinealglandAnteriorpituitaryHypothalamusPituitaryglandHypothalamusThalamusCerebrum

  • Hypothalamus controlPosterior pituitary (direct)Stimulation in hypothalamus Causes release of hormone from axon in ppADH released increased blood osmolalityOxytocin released due to baby suckling

  • HypothalamusPosteriorpituitaryAnteriorpituitaryNeurosecretory cells of the hypothalamusHypothalamusAxonHORMONEOxytocinADHKidney tubulesTARGETMammary glands, uterine muscles

  • Hypothalamus controlControls release of AP hormonesNeurons in Hypothalamus secrete releasing or inhibiting hormones Anterior Pituitary (negative feedback)

  • Hypothalamus

  • thyroidColdPathwayStimulusHypothalamus secretes thyrotropin-releasing hormone (TRH ) ExampleSensory neuronNeurosecretory cellBlood vessel+Anterior pituitary secretesthyroid-stimulatinghormone (TSHor thyrotropin )

  • thyroidColdPathwayStimulusHypothalamus secretes thyrotropin-releasing hormone (TRH )Negative feedbackExampleSensory neuronNeurosecretory cellBlood vesselAnterior pituitary secretes thyroid-stimulating hormone (TSH or thyrotropin )Target cellsResponseBody tissuesIncreased cellular metabolismThyroid gland secretes thyroid hormone (T3 and T4 )

  • Anterior pituitaryHypothalamic releasing and inhibiting hormonesNeurosecretory cells of the hypothalamusHORMONETARGETPosterior pituitaryPortal vesselsEndocrine cells of the anterior pituitaryPituitary hormonesTropic effects only: FSH LH TSH ACTHNontropic effects only: Prolactin MSH Nontropic and tropic effects: GH Testes or ovariesThyroidFSH and LHTSHAdrenal cortexMammary glandsACTHProlactinMSHGHMelanocytesLiver, bones, other tissues

  • Problems ThyroidGraves diseaseOver production of thyroxineCretinismTo little thyroxine in childrenLeads to delayed skeletal and mental growth

  • Hyperthyroidism

  • Negative feedback

  • Problems Diabetes mellitusDecreased insulinDecreased response to insulinIncreased blood sugar

  • Diabetes

  • Problems Growth hormone (anterior pituitary)Gigantism too much hormonePituitary dwarfism to little hormoneAcromegaly to much hormone after growth plates are fused

  • Acromegaly

  • ProblemsAddisons diseaseInsufficiency in ACTHIncreased pigmentation of skinImbalance of electrolytes

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