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Endocrine System Glands & Hormones

Endocrine System Glands & Hormones. Regulation & Communication. Animals rely on 2 systems for regulation endocrine system system of ductless glands secrete chemical signals directly into blood chemical travels to target tissue target cells have receptor proteins

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Endocrine System Glands & Hormones

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  1. Endocrine System Glands & Hormones

  2. Regulation & Communication • Animals rely on 2 systems for regulation • endocrine system • system of ductless glands • secrete chemical signals directly into blood • chemical travels to target tissue • target cells have receptor proteins • slow, long-lasting response • nervous system • system of neurons • transmits “electrical” signal & release neurotransmitters to target tissue • fast, short-lasting response

  3. Why are hormones needed? • Send chemical messages from one body part to another • Long term communication • Daily homeostasis & regulation • solute levels in blood • Glucose, Ca++, Na+ • Osmoregulation • Metabolism • Growth • Reproduction • Stress

  4. Regulation by chemical messengers • Neurotransmitters released by neurons • Hormones release by endocrine glands endocrine gland neurotransmitter axon hormone carried by blood receptor proteins receptor proteins target cell

  5. Classes of Hormones

  6. Action of lipid (steroid) hormones steroid hormone target cell blood S 1 S cross cell membrane protein carrier S 2 cytoplasm binds to receptor protein becomes transcription factor 5 mRNA read by ribosome S 3 plasma membrane 4 DNA mRNA 6 7 nucleus protein protein secreted ex: secreted protein = growth factor (hair, bone, muscle, gametes)

  7. signal-transduction pathway Action of protein hormones 1 signal proteinhormone plasma membrane P activates G-protein binds to receptor protein activates enzyme cAMP acts as 2° messenger receptorprotein ATP transduction GTP activatescytoplasmicsignal ATP activates enzyme 2 secondary messengersystem activates enzyme cytoplasm response 3 produces an action target cell

  8. adrenal gland Action of epinephrine (adrenaline) signal 1 epinephrine activatesG protein 3 activatesadenylyl cyclase receptor protein in cell membrane cAMP GDP transduction 4 ATP 2 GTP activates protein kinase-A 5 activates GTP activates phosphorylase kinase cytoplasm releasedto blood activates glycogen phosphorylase 7 glycogen glucose 6 liver cell response

  9. Benefits of a 2° messenger system Amplification! 1 signal Activated adenylyl cyclase receptor protein Not yet activated 2 amplification 4 amplification 3 cAMP 5 amplification GTP G protein protein kinase 6 amplification enzyme FAST response! 7 amplification product

  10. high low Maintaining homeostasis hormone 1 lowersbody condition gland specific body condition raisesbody condition gland Negative FeedbackModel hormone 2

  11. hypothalamus hypothalamus high low Nervous System Control Negative Feedback Controlling Body Temperature nerve signals sweat dilates surfaceblood vessels body temperature (37°C) constricts surfaceblood vessels shiver nerve signals

  12. pancreas high liver low pancreas liver Endocrine System Control Negative Feedback Regulation of Blood Sugar islets of Langerhansbeta cells insulin body cells takeup sugar from blood liver storesglycogen reducesappetite blood sugar level (90mg/100ml) liver releasesglucose triggershunger islets of Langerhansalpha cells glucagon

  13. osmoreceptors inhypothalamus increasethirst nephron nephron high JuxtaGlomerularApparatus low nephron (JGA) adrenalgland Endocrine System Control Negative Feedback Blood Osmolarity ADH increasedwaterreabsorption pituitary blood osmolarity blood pressure increasedwater & saltreabsorption renin aldosterone angiotensinogen angiotensin

  14. Nervous & Endocrine systems linked • Hypothalamus = “master nerve control center” • nervous system • receives information from nerves around body about internal conditions • releasing hormones: regulates release of hormones from pituitary • Pituitary gland = “master gland” • endocrine system • secretes broad rangeof “tropic” hormones regulating other glands in body hypothalamus posterior pituitary anterior

  15. Tropic hormones = target endocrine glands hypothalamus thyroid-stimulating hormone (TSH) antidiuretic hormone (ADH) posterior pituitary Thyroid gland anterior pituitary Kidney tubules adrenocorticotropic hormone (ACTH) oxytocin Muscles of uterus gonadotropic hormones: follicle- stimulating hormone (FSH) & luteinizing hormone (LH) melanocyte-stimulating hormone (MSH) growth hormone (GH) prolactin (PRL) Adrenal cortex Melanocyte Mammary glands Bone and muscle Ovaries Testes

  16. Pituitary Dwarfism

  17. Gigantism

  18. Acromegaly

  19. Regulating metabolism • Hypothalamus • TRH = TSH-releasing hormone • Anterior Pituitary • TSH = thyroid stimulating hormone • Thyroid • produces thyroxine hormones • metabolism & development • bone growth • mental development • metabolic use of energy • blood pressure & heart rate • muscle tone • digestion • reproduction tyrosine + iodine thyroxine

  20. Goiter Iodine deficiency causes thyroid to enlarge as it tries to produce thyroxine + ✗ tyrosine + iodine ✗ thyroxine

  21.  kidney reabsorption of Ca++ thyroid Ca++ depositedin bones high  Ca++uptakein intestines low parathyroid  kidney reabsorption of Ca++ bones release Ca++ Negative Feedback Endocrine System Control Regulation of Blood Calcium calcitonin blood calcium level(10 mg/100mL) activated Vitamin D parathyroid hormone (PTH)

  22. corpusluteum ovary yes corpusluteum no Negative Feedback Female reproductive cycle eggmatures & is released(ovulation) builds up uterus lining estrogen progesterone FSH & LH fertilized egg(zygote) maintainsuterus lining pituitarygland hCG pregnancy progesterone GnRH corpus luteum breaks down progesterone drops menstruation hypothalamus maintainsuterus lining

  23. Positive Feedback Oxytocin

  24. Positive Feedback

  25. Effects of stress on a body Stress Nerve signals Hypothalamus Spinal cord (cross section) Releasing hormone Nerve cell Anterior pituitary Blood vessel adrenal medulla secretes epinephrine & norepinephrine Nerve cell Adrenal cortex secretes mineralocorticoids & glucocorticoids ACTH Adrenal gland Kidney CORTEX MEDULLA (A) SHORT-TERM STRESS RESPONSE (B) LONG-TERM STRESS RESPONSE Effects of glucocorticoids: 1. Proteins & fats broken down & converted to glucose, leading to increased blood glucose 2. Immune system suppressed Effects of epinephrine and norepinephrine: 1. Glycogen broken down to glucose; increased blood glucose 2. Increased blood pressure 3. Increased breathing rate 4. Increased metabolic rate 5. Change in blood flow patterns, leading to increased alertness & decreased digestive & kidney activity Effects of mineralocorticoids: 1. Retention of sodium ions & water by kidneys 2. Increased blood volume & blood pressure

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