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Endocrine system


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Endocrine system

  1. 1. Part 1 - OverviewEndocrine System
  2. 2. Nervous vs Endocrine SystemNervous system: coordinates rapid responsesto stimuli via action potentials (electricalsignal)Endocrine system: coordinates long-termresponses using chemical signals (hormones)
  3. 3. Integration of nervous andendocrineinterneuronsBrainandSpinalCordCentral Nervous System Peripheral Nervous SystemExternal sensesInternal sensesneurons2. Integration: processingby the CNSParasympatheticSympatheticneurons3. Motor output:response by effectorcells1. Sensory input: detectionby sensory receptors
  4. 4. Dual roles of some hormonesSome chemicals are both hormones in theendocrine system and signals in the nervoussystemExample: epinephrine“flight or fight” hormone produced by adrenalmedulla (endocrine gland)Neurotransmitter that conveys message betweenneurons
  5. 5. HormonesChemical signals carried by blood and causespecific changes in target cellsFunction:regulate energy use, metabolism and growthmaintain homeostasis
  6. 6. Target CellCells that respond to a regulatory signalE.g. have specific receptors for hormonesPerforms the body’s response to thehormonal signals
  7. 7. Types of HormonesPeptide HormonesSteroid Hormones
  8. 8. Peptide Hormoneshort peptidesequenceswater solubleCannot pass throughcell membrane(phospholipid)Binds to receptor onsurface of target celland triggers a signaltransduction pathway
  9. 9. Steroid Hormonemade from cholesterolinsoluble in water, lipid-solubleCan enter target cell bydiffusion through cellmembraneBind to intracellularreceptor in cytoplasm ornucleus
  10. 10. GlandsEndocrine glands: organs producinghormones delivered by blood streamBlood vessels are considered “inside” your body =endoExocrine glands: organs producinghormones delivered by ductsDucts are considered “outside” the body = exo
  11. 11. Example of Exocrine GlandsDigestive system:digestive glands(pancreas)salivary glandsThermoregulation:sweat glands
  12. 12. Human endocrine glandsFig. 45.5
  13. 13. HypothalamusIntegrates the endocrine and nervous systemInput: Internal sensesSignals from the inside of the body travel throughafferent neurons to hypothalamusOutput: HormonesEffector neurons secrete hormones that act onglands of the autonomic nervous system
  14. 14. HypothalamusNeurosecretorycells: specializednerve cells thatsecrete hormones
  15. 15. Pituitary Glandlocated at the base of the hypothalamus2 parts: anterior & posterior
  16. 16. Posterior PituitaryExtension of the brain(hypothalamus)Does not makehormones itselfStores and secreteshormones that weresynthesized by theneurosecretory cells inthe hypothalamus2 hormones releasedfrom posterior pituitary:ADH & oxytocin
  17. 17. Anterior PituitaryNot developed from the brainA separate structure from the hypothalamusConnected to hypothalamus by portal blood vesselMakes its own set of hormones that are stimulated orinhibited by hormones produced in the hypothalamus
  18. 18. HypothalamusNeurosecretory cellssynthesize 2 types ofhormones that are sentto the anterior pituitaryReleasing hormone:stimulate gland tosecrete hormonesInhibiting hormone:inhibit gland fromsecreting hormones
  19. 19. Regulating Hormone Secretionin Anterior Pituitary1. Secretory cells in the hypothalamusproduce releasing or inhibiting hormones2. Portal blood vessels (capillaries) allowhormones from the hypothalamus toaccess cells in the anterior pituitary3. Endocrine (secretory) cells of the pituitarysynthesize and secrete hormones into theblood
  20. 20. Anterior PituitaryMany hormones producedin the anterior pituitaryThe ones you willeventually need to know:GHPRLLH, FSHTSHACTH
  21. 21. Anterior Pituitary
  22. 22.
  23. 23. Patterns of Hormonal ControlEndocrinepathwayNeurohormonepathwayNeuroendocrinepathwayStimulusEndocrine cellBlood vesselTargetResponseStimulusHypothalamusBlood vesselTargetResponseStimulusHypothalamusBlood vesselEndocrine cellBlood vesselTargetResponse
  24. 24. Endocrine PathwayStimulus signals endocrine glands to producehormones. Bypasses the nervous system entirely.Examples:Stimulus Blood glucose Blood PressureGland Pancreas AdrenalHormone Insulin / glucagon AldosteroneTarget cells Body cells In collecting duct
  25. 25. Endocrine Pathway Example:Aldosterone
  26. 26. Neurohormone PathwayStimulus signals hypothalamus to producehormones that directly act on target cellswithout stimulating endocrine glands
  27. 27. Neurohormone Pathway Example:Posterior Pituitary HormonesFig. 45.6a
  28. 28. Neurohormone Pathway Example:ADHTARGETCells
  29. 29. Neuroendocrine PathwayStimulus signals hypothalamusto produce hormones whichthen signals endocrine glandsto produce other hormonesAll the examples come fromhormones of the anteriorpituitaryFig. 45.6b
  30. 30. Tropic HormoneTarget other endocrine glands rather than thefinal target cellStimulate the synthesis and release ofhormones from other endocrine glands
  31. 31. Neuroendocrine PathwayWhich one is a tropic hormone?Fig. 45.6bIGF-1 Milk (not ahormone)SpermatogenesisEstrogen,ProgesteroneT3/T4 Corticosteroidliver
  32. 32. Anterior Pituitary HormonesPage 963, Fig. 45.6Hormone Path TropicGrowth hormone (GH) NH/NE  Prolactin (PRL) NE Follicle stimulating hormone (FSH) NE  Lutenizing hormone (LH) NE Thyroid stimulating hormone (TSH) NE Adrenocorticotropic hormone (ACTH) NE 