1 / 41

Hormones and Feedback Mechanisms

Hormones and Feedback Mechanisms. Endocrine System. The Endocrine System. Overview Anatomy Glands Hormones. I. A General Overview. ES (endocrine system) and homeostasis Anatomy Glands Hormones Target cells ES as a Control System Hormone + target cell = return to homeostasis.

sierra
Télécharger la présentation

Hormones and Feedback Mechanisms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HormonesandFeedback Mechanisms

  2. Endocrine System

  3. The Endocrine System • Overview • Anatomy • Glands • Hormones

  4. I. A General Overview • ES (endocrine system) and homeostasis • Anatomy • Glands • Hormones • Target cells • ES as a Control System • Hormone + target cell = return to homeostasis

  5. ES and Homeostasis • Homeostasis

  6. II. Anatomy Glands – produce and secrete hormones

  7. C. Hormones • Chemical messenger • Type of Protein • Specific to target cell • Travel in bloodstream

  8. Hormone + Receptor

  9. Hypothalamus RH = Pituitary releasing hormones RIH = Pituitary release inhibiting hormones

  10. Why is the Hypothalamus so Important? • "Directs" pituitary gland

  11. STIMULUS Hypothalamus Releasing Hormone (Release-Inhibiting Hormone) Pituitary Stimulating Hormone Gland Hormone Target

  12. Pituitary gland • MASTER GLAND

  13. 2. Anterior Pituitary Hormones

  14. III.Control of Endocrine Function • Positive • or Negative Feedback mechanisms • Self-regulating system

  15. STIMULUS Hypothalamus Releasing Hormone (Release-Inhibiting Hormone) Pituitary Stimulating Hormone Gland Hormone Target

  16. A. Positive Feedback • Not common • Classic example: Action of OXYTOCIN on uterine muscle during birth.

  17. Positive Feedback • Baby pushes on cervix • Nervous signal to Hypothalamus • Hypothal. manufactures OXY • OXY transported to POSTERIOR PITUITARY & released • OXY stimulates uterine contraction • Loop stops when baby leaves birth canal

  18. B. Negative Feedback • Most common control mechanism • Level of hormone in blood or body’s return to homeostasis shuts off loop at hypothalamus and pituitary

  19. Negative Feedback: Thyroid

  20. Basic Structure of Feedback Loop • Stimulus • Hypothalamus Pituitary • Pituitary Target area • Target area produces change • Change acts negatively or positively on the cycle.

  21. IV. Specific Endocrine Events • Thyroid Hormone • Growth Hormone • Adrenal Cortex Hormones • Sex Steroids

  22. Thyroid • Controls rate of metabolism • Hormones • T3 and T4

  23. Hyperthyroidism and Goiter

  24. Hypersecretion of TSH or TH

  25. Hyposecretion of TH

  26. B. Growth Hormone • Stimulus = Tissue growth/ repair • Hypothalamus releases GHRH • Anterior Pituitary releases GH •  Protein synthesis, growth, etc. • GH and release of somatostatin shuts off GHRH and GH release

  27. What happens with excess GH?

  28. GH as Juvenile

  29. GH as an Adult

  30. How Does Hypersecretion of GH Happen?

  31. GH = pituitary dwarfism

  32. Adrenal Gland • Adrenal gland located atop kidney • Outer part = cortex • Secretes Cortisol (stress), Androgens, Aldosterone (electrolytes) • Inner part = medulla • SNS control • Secretes EPI & NEPI (fight or flight)

  33. Adrenal Insufficiency • Addison’s disease--hyposecretion of cortisol • JFK • Darkened skin (ACTH mimics MSH) • Weight loss, hypoglycemia • Find the anomaly in the feedback loop. • Inability to handle stress

  34. 4. Sex Steroids • Stimulus = low circulating T or E • Hypothalamus = GnRH • Anterior Pituitary = FSH & LH • Gonads produce T and E • High T and E shut off GnRH and FSH/LH

  35. Too many steroids

More Related