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Endocrine System Hormones & Homeostasis

Endocrine System Hormones & Homeostasis. Homeostasis. Homeostasis maintaining internal balance in the body organism must keep internal conditions stable even if environment changes also called “ dynamic equilibrium ” example: body temperature humans: too cold = shiver too warm = sweat

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Endocrine System Hormones & Homeostasis

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  1. Endocrine System Hormones& Homeostasis

  2. Homeostasis • Homeostasis • maintaining internal balance in the body • organism must keep internal conditions stable even if environment changes • also called “dynamic equilibrium” • example: body temperature • humans: • too cold = shiver • too warm = sweat • lizard: • too cold = bask in sun • too warm = hide in shade

  3. Regulation • How we maintain homeostasis • nervous system • nerve signals control body functions • endocrine system • hormones • chemical signals control body functions

  4. high low Nervous System Control Feedback Controlling Body Temperature nerve signals brain sweat dilates surfaceblood vessels body temperature brain constricts surfaceblood vessels shiver nerve signals

  5. Hormones • Why are hormones needed? • chemical messages from one body part to cells in other parts of body • communication needed to coordinate whole body • maintaining homeostasis growth hormones

  6. Endocrine System • Endocrine system releases hormones • glands which secrete (release) chemical signals into blood • chemicals cause changes in other parts of body • growth hormones • sex hormones • response hormones • metabolism hormones • and more….

  7. Responding to hormones • Lock and key system • hormone fits receptor on “target” cell targetcell secretingcell non-targetcells can’treadsignal can’treadsignal

  8. Glands • Pineal • melatonin • Pituitary • many hormones: master gland • Thyroid • thyroxine • Adrenal • adrenaline • Pancreas • insulin, glucagon • Ovary • estrogen • Testes • testosterone

  9. high low Feedback Maintaining homeostasis hormone 1 lowersbody condition gland specific body condition raisesbody condition gland hormone 2

  10. high Negative Feedback • Response to changed body condition • if body is high or low from normal level • signal tells body to make changes that will bring body back to normal level • once body is back to normal level, signal is turned off hormone 1 lowersbody condition gland specific body condition

  11. pancreas high liver low pancreas liver Endocrine System Control Feedback Regulation of Blood Sugar insulin body cells takeup sugar from blood liver storessugar reducesappetite blood sugar level (90mg/100ml) liver releasessugar triggershunger glucagon

  12. Everyone’s doing it, so Ask Questions!!

  13. Sex & Growth Hormones • Large scale body changes • how do they work • turn genes on • start new processes in the body by turning genes on that were lying “dormant”

  14. Pituitary gland hormones • Sex & reproductive hormones • FSH • follicle stimulating hormone • stimulates egg & sperm production • LH • luteinizing hormone • stimulates ovaries & testes • prepares uterus for fertilized egg • oxytocin • stimulates childbirth contractions • releases milk in nursing mothers • prolactin • milk production in nursing mothers hormones hormones

  15. Reproductive hormones • Testosterone • from testes • sperm production & secondary sexual characteristics • Estrogen • from ovaries • egg production, preparing uterus for fertilized egg & secondary sexual characteristics

  16. Male reproductive system • Sperm production • over 100 million produced per day! • ~2.5 million released per drop!

  17. seminiferoustubule sperm spermatocytes

  18. Male reproductive system • Testes & epididymis • sperm production & maturation • Glands • seminal vesicles, prostate, bulbourethal • produce seminal fluid • nutrient-rich

  19. Male reproductive system • Testicles • produces sperm & hormones • Scrotum • sac that holds testicles outside of body • Epididymis • where sperm mature • Vas deferens • tubes for sperm to travel from testes to penis • Prostate, seminal vesicles, Cowper’s (bulbourethal) glands • nutrient rich fluid to feed & protect sperm

  20. Female reproductive system

  21. Female reproductive system • Ovaries • produces eggs & hormones • Uterus • nurtures fetus; lining builds up each month • Fallopian tubes • tubes for eggs to travel from ovaries to uterus • Cervix • opening to uterus, dilates 10 cm for birthing baby • Vagina • birth canal for birthing baby

  22. Female reproductive system

  23. Egg maturation in ovary releasesprogesterone maintainsuteruslining produces estrogen

  24. LH Menstrual cycle • Controlled by interaction of 4 hormones • FSH & LH • estrogen • progesterone FSH ovulation = egg release egg development corpus luteum estrogen progesterone lining of uterus days 0 7 14 21 28

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

  26. Female hormones • FSH & LH • released from pituitary • stimulates egg development & hormone release • peak release = release of egg (ovulation) • Estrogen • released from ovary cells around developing egg • stimulates growth of lining of uterus • decreasing levels causes menstruation • Progesterone • released from “corpus luteum” in ovaries • cells that used to take care of developing egg • stimulates blood supply to lining of uterus • decreasing levels causes menstruation

  27. Fertilization

  28. Any Questions??

  29. What do they do? Body Temperature • Maintain homeostasis • blood sugar level • temperature control • Start a new process • growth • fetal development • sexual development

  30. Negative Feedback • Negative feedback • every time body is high or low from normal level a signal tells the body to make changes that will bring body back • body temperature • control of blood sugar

  31. 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

  32. hormones hormones Body Regulation • Nervous system & Endocrine system work together • hypothalamus • “master nerve control center” • receives information from nerves around body about internal conditions • communicates with pituitary gland • “master gland” • releases many hormones • sexual development, growth, milk production, pain-relief

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