1. POWERPOINT ® LECTURE SLIDE PRESENTATION by ZARA OAKES, MS, The University of Texas at Austin Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HUMAN PHYSIOLOGY AN INTEGRATED APPROACH FOURTH EDITION DEE UNGLAUB SILVERTHORN UNIT 2 PART A 7 Introduction to the Endocrine System

2. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings About this Chapter  Function and purpose of hormones  Classification, structure, and synthesis of hormones  Pathways of nervous to endocrine regulation  Effects of hormone interactions  Pathologies of the endocrine system  Hormone evolution

3. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy Summary: Hormones Figure 7-2 (1 of 4)

4. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-2 (2 of 4) Anatomy Summary: Hormones

5. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy Summary: Hormones Figure 7-2 (3 of 4)

6. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-2 (4 of 4) Animation: Endocrine System: Endocrine System Review PLAY Anatomy Summary: Hormones

7. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings General Information on Hormones Chemical Regulating Systems  Hormones  Depend on cell to cell communication molecules  Made in gland(s) or cells  Transported by blood  Distant target tissue receptors  Activates physiological response  Pheromones: organism to organism communication Hormone Function  Control rates of enzymatic reactions, transport of ions or molecules across cell membranes, and gene expression and protein synthesis  Exert effects at very low concentrations  Bind to target cell receptors  Half-life indicates length of activity

8. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings PLAY Hormones: Classification  Peptide or protein hormones  Molecular structure includes amino acid chains  Water soluble and lipophobic = bind cell receptor  short life-time but triggers rapid respondses  Steroid hormones  Molecular structure includes a cholesterol molecule.  Made only in few organs (adrenal gland, gonads, placenta)  Not water soluble, lipophobic  Enters the nucleus, affects transcription= genomic effect  Amine hormones  Small hormone derived from tryptophan and tyrosine  Catecholamines- epinephrine, norepinephrine, and dopamine are neurohormones that are lipophobic  Thyroid hormones – T3, T4, Thyroxine, are lipophilic and bind intracellular receptors

9. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hormones: Peptides or Proteins  Preprohormone  Large, inactive- before being processed they may have multiple copies of a peptide hormone  Prohormone  Post-translational modification - inactive prehormones are cleaved by proteolytic enzymes  Peptide hormone-receptor complex  Signal transduction system -

10. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Peptide Hormone Synthesis, Packaging, and Release Figure 7-3 4 5 To target Active hormone Golgi complex Secretory vesicle ECFCytoplasmPlasma Peptide fragment Release signal Capillary endothelium Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone. The chain is directed into the ER lumen by a signal sequence of amino acids. The secretory vesicle releases its contents by exocytosis into the extracellular space. The hormone moves into the circulation for transport to its target. Enzymes in the ER chop off the signal sequence, creating an inactive prohormone. The prohormone passes from the ER through the Golgi complex. Secretory vesicles containing enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments. mRNA Ribosome Prohormone Signal sequence Transport vesicle Endoplasmic reticulum (ER) Preprohormone 123 6 1 2 3 4 5 6

11. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Peptide Hormone-Receptor Complex Membrane receptors and signal transduction for peptide hormones Figure 7-5 Surface receptor Hormone binds Enzyme activation Open channels Second messenger systems Cellular response Surface receptor Hormone binds Enzyme activation Open channels Second messenger systems Cellular response

12. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Features  Cholesterol-derived- made only in a few organs, synthesized as needed, not stored.  Lipophilic and can enter target cell -  Cytoplasmic or nuclear receptors (mostly) – binds receptors intracellularly  Activate DNA for protein synthesis – receptor- hormone complexes act as transcription factors.  Slower acting, longer half-life – because of it’s slow rate of activation they do not mediate reflex pathways.  Examples-  Cortisol, estrogen, and testosterone

13. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Structure Steroid hormones are derived from cholesterol Figure 7-6

14. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Action Figure 7-7 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. Translation produces new proteins for cell processes. Some steroid hormones also bind to mem- brane receptors that use second messenger systems to create rapid cellular responses. Steroid hormone receptors are typically in the cytoplasm or nucleus. The receptor- hormone complex binds to DNA and activates or represses one or more genes. Activated genes create new mRNA that moves into the cytoplasm. Cell membrane Interstitial fluid Cytoplasmic receptor Endoplasmic reticulum Nucleus Nuclear receptor DNA Translation Rapid responses Transcription produces mRNA Steroid hormone Blood vessel Protein carrier New proteins Cell surface receptor 2 3 1 4 5 2a 1 2 3 4 5

15. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Action Figure 7-7, steps 1–2a Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. Some steroid hormones also bind to mem- brane receptors that use second messenger systems to create rapid cellular responses. Steroid hormone receptors are typically in the cytoplasm or nucleus. Cell membrane Interstitial fluid Cytoplasmic receptor Nucleus Nuclear receptor Rapid responses Steroid hormone Blood vessel Protein carrier Cell surface receptor 2 1 2a 1 2

16. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Action Figure 7-7, steps 1–4 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. Some steroid hormones also bind to mem- brane receptors that use second messenger systems to create rapid cellular responses. Steroid hormone receptors are typically in the cytoplasm or nucleus. The receptor- hormone complex binds to DNA and activates or represses one or more genes. Activated genes create new mRNA that moves into the cytoplasm. Cell membrane Interstitial fluid Cytoplasmic receptor Nucleus Nuclear receptor DNA Rapid responses Transcription produces mRNA Steroid hormone Blood vessel Protein carrier Cell surface receptor 2 3 1 4 2a 1 2 3 4

17. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Steroid Hormones: Action Figure 7-7, steps 1–5 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. Translation produces new proteins for cell processes. Some steroid hormones also bind to mem- brane receptors that use second messenger systems to create rapid cellular responses. Steroid hormone receptors are typically in the cytoplasm or nucleus. The receptor- hormone complex binds to DNA and activates or represses one or more genes. Activated genes create new mRNA that moves into the cytoplasm. Cell membrane Interstitial fluid Cytoplasmic receptor Endoplasmic reticulum Nucleus Nuclear receptor DNA Translation Rapid responses Transcription produces mRNA Steroid hormone Blood vessel Protein carrier New proteins Cell surface receptor 2 3 1 4 5 2a 1 2 3 4 5

18. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Amine Hormones: Features  Derived from one of two amino acids  Tryptophan – double ring amino acid  Tyrosine-single ring amino acid  Ring structure-  Thyroid hormones- bind intracellular receptors.  Catecholamines- neurohormones that bind cell membrane receptors  Epinephrine -  Norepinephrine -  Dopamine -

19. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings PLAY Endocrine Reflex Pathways  Stimulus Hormones may have multiple stimuli for their release and endocrine cells act as the receptor  Afferent signal input signal  Integration The cells that make the hormone must interpret the various signals and decide how much to produce.  Efferent signal Out put signal=hormone  Physiological action  Negative feedback

20. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Pituitary Gland Anatomy Figure 7-11

21. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-12 The Pituitary Gland: Two Fused Posterior pituitary produces 1. Vasopressin (also called ADH) 2. Oxytocin Posterior pituitary produces 1. Vasopressin (also called ADH) 2. Oxytocin

22. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-16 The Hypothalamic-Hypophyseal Portal System

23. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Pituitary Gland: Two Fused Hormones of the hypothalamic-anterior pituitary pathway Figure 7-13

24. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Endocrine Control  Three levels  Hypothalamic stimulation—from CNS  Pituitary stimulation— from hypothalamic trophic hormones  Endocrine gland stimulation—from pituitary trophic hormones  Long-loop feedback  Short-loop feedback

25. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Comparing two control Pathways Figure 7-15 Two types of Neuro hormones: 1.Adrenal medulla Catecholamines 2. Hypothalamus Anterior pituitary Posterior pituitary Two types of Neuro hormones: 1.Adrenal medulla Catecholamines 2. Hypothalamus Anterior pituitary Posterior pituitary

26. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hormone Interactions  Synergism  Multiple stimuli—more than additive  Permissiveness  Need second hormone to get full expression  Antagonism  Glucagons opposes insulin

27. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Endocrine Pathologies  Hormone disease is caused by an imbalance due to either excess or deficiency or abnormal responsiveness  Hypersecretion: excess hormone causes exaggerated effects  Tumors (benign or cancerous) of glandular tissues  Exogenous sources- most sources are medications or suppliments, can cause gland atrophy  Grave’s disease—high secretion of thyroxin-  Hyposecretion: deficient hormone  Most often low levels cause increased tropic hormone levels  Goiter— low secretion of thyroxin  Diabetes—low secretion of insulin  Abnormalities related to hormone response  Target tissues do not respond to the hormone correctly  Downregulation- high hormone levels may result in a decrease of receptors as it happens in Hyperinsulinemia  Receptor abnormalities- the receptors may not function due to a genetic mutation as it happens in Testicular feminization syndrome

28. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-19 Endocrine Pathologies  Exogenous medication  Replaces and exceeds normal  Cause atrophy of gland

29. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7-20 PLAY Primary and Secondary Pathologies Primary and Secondary hypersecreti ons are caused by abnormalitie s of different glands along the hormone release path

30. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Pineal Gland and Melatonin  Influences body clock- sets sleep-wake cycles  Antioxidant activity- neutralizes free radicals  Other roles need research  SAAD - seasonal affective depressive disorder  sexual behavior- sexual function and the onset of puberty

31. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Pineal Gland and Melatonin Figure 7-22 (1 of 3)