 hormones & endocrine system. introduction  endocrine system – sum of all hormone secreting...

Download  Hormones & Endocrine System. Introduction  Endocrine System – Sum of all hormone secreting cells and tissues  Endocrine Gland – ductless glands that

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  • IntroductionEndocrine System Sum of all hormone secreting cells and tissuesEndocrine Gland ductless glands that secrete hormones directly into body fluidsHormones chemical signals that cause a response in target cellsAffect body tissues or other endocrine glands (tropic hormone)Endocrine secretion is determined by Positive & Negative Feedback

  • HormonesCan affect 1 tissue, multiple tissues or entire body

    Can also have a direct effect on non-endocrine tissuesOR affect other endocrine tissuesCalled tropic hormones

  • Target Cell ReceptorsCell-Surface ReceptorsMost common receptor for initiating a signal transduction pathwayReceptor Transduction ResponseIntracellular ReceptorsONLY lipid-soluble ligands are able to pass through the membrane & bind intracellular receptorsTestosterone & estrogen (transcription factors)

  • Hypothalamus & PituitaryHypothalamus gets info from the brain or nervesHypothalamus initiates endocrine signal response

    Pituitary Anterior & PosteriorPosterior - Extension of the hypothalamus that stores and secretes hormonesAnterior tropic hormones (say what???)

  • The BossHypothalamusReceives signals from nervous systemInitiates endocrine signal response

    Note HypothalamusPituitary Gland

  • Anterior Pituitary GlandRegulated by hypothalamusTropic hormones

    Growth hormone (GH) & Thyroid-stimulating hormone (TSH) seriously?ACTH Adrenocorticotropic hormoneStimulates adrenal cortex to secrete glucocortocoidsGlucocortocoids raise the blood sugar level

  • Anterior Pituitary Gland (page 2)

    FSH (Follicle stimulating Hormone)Stimulates development of ovarian follicles (female) or spermatogenesis in seminiferous tubules (male)

    LH (Luteinizing Hormone)Triggers ovulation in femalesStimulates testosterone production in testes

    PRL (Prolactin)Stimulates growth of mammary glandsmilk production & synthesis of milk protein

  • Posterior PituitaryOxytocinStimulates uterine contractionsStimulates milk release by mammary glandsADH (Antidiuretic Hormone)Acts on collecting ducts in KidneysIncreases water reabsorption from the filtrate

  • Thyroid & ParathyroidT3 (Triiodothyronine) & T4 (Thyroxine)Stimulates & maintain metabolic processesCalcitoninLowers calcium level in bloodParathyroid GlandPTH (Parathyroid)Raises calcium level in blood

  • Adrenal GlandEpinephrine & norepinephrine Increase metabolic level by:Constrict blood vesselsRaise blood glucose levelsGlucocorticoidsElevate blood glucose levelACTH

  • Pancreas & Pineal GlandPancreasInsulin Lowers blood glucose levelMakes cells permeable to glucoseGlucagon Raises blood glucose levelBreaks down glycogen

    Pineal GlandMelatonin Involved in biological rhythms

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