Start Here Ch18 Lecture


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Start Here Ch18 Lecture

  1. 1. :) The Endocrine System PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris
  2. 2. Introduction to the Endocrine System <ul><li>Figure 18–1 Organs and Tissues of the Endocrine System. </li></ul>
  3. 3. Introduction to the Endocrine System <ul><li>Figure 18–1 Organs and Tissues of the Endocrine System. </li></ul>:)
  4. 4. Introduction to the Endocrine System <ul><li>The Endocrine System </li></ul><ul><ul><li>Regulates long-term processes </li></ul></ul><ul><ul><ul><li>Growth </li></ul></ul></ul><ul><ul><ul><li>Development </li></ul></ul></ul><ul><ul><ul><li>Reproduction </li></ul></ul></ul><ul><ul><li>Uses chemical messengers to relay information and instructions between cells </li></ul></ul>:)
  5. 5. Homeostasis and Intercellular Communication <ul><li>Direct Communication </li></ul><ul><ul><li>Exchange of ions and molecules between adjacent cells across gap junctions </li></ul></ul><ul><ul><li>Occurs between two cells of same type </li></ul></ul><ul><ul><li>Highly specialized and relatively rare </li></ul></ul>:)
  6. 6. Homeostasis and Intercellular Communication <ul><li>Paracrine Communication </li></ul><ul><ul><li>Uses chemical signals to transfer information from cell to cell within single tissue </li></ul></ul><ul><ul><li>Most common form of intercellular communication </li></ul></ul>:)
  7. 7. Homeostasis and Intercellular Communication <ul><li>Endocrine Communication </li></ul><ul><ul><li>Endocrine cells release chemicals ( hormones ) into bloodstream </li></ul></ul><ul><ul><li>Alters metabolic activities of many tissues and organs simultaneously </li></ul></ul>:)
  8. 8. Homeostasis and Intercellular Communication <ul><li>Target Cells </li></ul><ul><ul><li>Are specific cells that possess receptors needed to bind and “read” hormonal messages </li></ul></ul><ul><li>Hormones </li></ul><ul><ul><li>Stimulate synthesis of enzymes or structural proteins </li></ul></ul><ul><ul><li>Increase or decrease rate of synthesis </li></ul></ul><ul><ul><li>Turn existing enzyme or membrane channel “on” or “off” </li></ul></ul>:)
  9. 9. Homeostasis and Intercellular Communication :)
  10. 10. Homeostasis and Intercellular Communication :)
  11. 11. Hormones <ul><li>Can be divided into three groups </li></ul><ul><ul><li>Amino acid derivatives </li></ul></ul><ul><ul><li>Peptide hormones </li></ul></ul><ul><ul><li>Lipid derivatives </li></ul></ul><ul><li>Circulate freely or bound to transport proteins </li></ul>:)
  12. 12. Hormones <ul><li>Figure 18–2 A Structural Classification of Hormones </li></ul>:)
  13. 13. Secretion and Distribution of Hormones <ul><li>Free Hormones </li></ul><ul><ul><li>Remain functional for less than 1 hour </li></ul></ul><ul><ul><ul><li>Diffuse out of bloodstream: </li></ul></ul></ul><ul><ul><ul><ul><li>bind to receptors on target cells </li></ul></ul></ul></ul><ul><ul><ul><li>Are broken down and absorbed: </li></ul></ul></ul><ul><ul><ul><ul><li>by cells of liver or kidney </li></ul></ul></ul></ul><ul><ul><ul><li>Are broken down by enzymes: </li></ul></ul></ul><ul><ul><ul><ul><li>in plasma or interstitial fluids </li></ul></ul></ul></ul>:)
  14. 14. Secretion and Distribution of Hormones <ul><li>Thyroid and Steroid Hormones </li></ul><ul><ul><li>Remain in circulation much longer </li></ul></ul><ul><ul><li>Enter bloodstream </li></ul></ul><ul><ul><ul><li>More than 99% become attached to special transport proteins </li></ul></ul></ul><ul><ul><ul><li>Bloodstream contains substantial reserve of bound hormones </li></ul></ul></ul>:)
  15. 15. Mechanisms of Hormone Action <ul><li>Hormone Receptor </li></ul><ul><ul><li>Is a protein molecule to which a particular molecule binds strongly </li></ul></ul><ul><ul><li>Responds to several different hormones </li></ul></ul><ul><ul><li>Different tissues have different combinations of receptors </li></ul></ul><ul><ul><li>Presence or absence of specific receptor determines hormonal sensitivity </li></ul></ul>:)
  16. 16. Mechanisms of Hormone Action <ul><li>Hormones and Plasma Membrane Receptors </li></ul><ul><ul><li>Catecholamines and peptide hormones </li></ul></ul><ul><ul><ul><li>Are not lipid soluble </li></ul></ul></ul><ul><ul><ul><li>Unable to penetrate plasma membrane </li></ul></ul></ul><ul><ul><ul><li>Bind to receptor proteins at outer surface of plasma membrane (extracellular receptors) </li></ul></ul></ul>:)
  17. 17. Mechanisms of Hormone Action <ul><li>Hormones and Plasma Membrane Receptors </li></ul><ul><ul><li>Bind to receptors in plasma membrane </li></ul></ul><ul><ul><li>Cannot have direct effect on activities inside target cell </li></ul></ul><ul><ul><li>Use intracellular intermediary to exert effects </li></ul></ul><ul><ul><ul><li>First messenger: </li></ul></ul></ul><ul><ul><ul><ul><li>leads to second messenger </li></ul></ul></ul></ul><ul><ul><ul><ul><li>may act as enzyme activator, inhibitor, or cofactor </li></ul></ul></ul></ul><ul><ul><ul><ul><li>results in change in rates of metabolic reactions </li></ul></ul></ul></ul>:)
  18. 18. Mechanisms of Hormone Action <ul><li>Important Second Messengers </li></ul><ul><ul><li>Cyclic-AMP (cAMP) </li></ul></ul><ul><ul><ul><li>Derivative of ATP </li></ul></ul></ul><ul><ul><li>Cyclic-GMP (cGMP) </li></ul></ul><ul><ul><ul><li>Derivative of GTP </li></ul></ul></ul><ul><ul><li>Calcium ions </li></ul></ul>:)
  19. 19. Mechanisms of Hormone Action <ul><li>The Process of Amplification </li></ul><ul><ul><li>Is the binding of a small number of hormone molecules to membrane receptors </li></ul></ul><ul><ul><li>Leads to thousands of second messengers in cell </li></ul></ul><ul><ul><li>Magnifies effect of hormone on target cell </li></ul></ul>:)
  20. 20. Mechanisms of Hormone Action <ul><li>Down-regulation </li></ul><ul><ul><li>Presence of a hormone triggers decrease in number of hormone receptors </li></ul></ul><ul><ul><li>When levels of particular hormone are high, cells become less sensitive </li></ul></ul><ul><li>Up-regulation </li></ul><ul><ul><li>Absence of a hormone triggers increase in number of hormone receptors </li></ul></ul><ul><ul><li>When levels of particular hormone are low, cells become more sensitive </li></ul></ul>:)
  21. 21. Mechanisms of Hormone Action <ul><li>Hormones and Plasma Membrane Receptors </li></ul><ul><ul><li>G Protein </li></ul></ul><ul><ul><ul><li>Enzyme complex coupled to membrane receptor </li></ul></ul></ul><ul><ul><ul><li>Involved in link between first messenger and second messenger </li></ul></ul></ul><ul><ul><ul><li>Binds GTP </li></ul></ul></ul><ul><ul><ul><li>Activated when hormone binds to receptor at membrane surface and changes concentration of second messenger cyclic-AMP (cAMP) within cell: </li></ul></ul></ul><ul><ul><ul><ul><li>increased cAMP level accelerates metabolic activity within cell </li></ul></ul></ul></ul>:)
  22. 22. Mechanisms of Hormone Action <ul><li>Figure 18–3 G Proteins and Hormone Activity. </li></ul>:)
  23. 23. Mechanisms of Hormone Action <ul><li>Figure 18–3 G Proteins and Hormone Activity. </li></ul>:)
  24. 24. Mechanisms of Hormone Action <ul><li>G Proteins and Calcium Ions </li></ul><ul><ul><li>Activated G proteins trigger </li></ul></ul><ul><ul><ul><li>opening of calcium ion channels in membrane </li></ul></ul></ul><ul><ul><ul><li>release of calcium ions from intracellular stores </li></ul></ul></ul><ul><ul><ul><li>G protein activates enzyme phospholipase C (PLC) </li></ul></ul></ul><ul><ul><ul><li>Enzyme triggers receptor cascade: </li></ul></ul></ul><ul><ul><ul><ul><li>production of diacylglycerol (DAG) and inositol triphosphate (IP 3 ) from membrane phospholipids </li></ul></ul></ul></ul>:)
  25. 25. Mechanisms of Hormone Action <ul><li>Figure 18–3 G Proteins and Hormone Activity. </li></ul>:)
  26. 26. Mechanisms of Hormone Action <ul><li>Hormones and Intracellular Receptors </li></ul><ul><ul><li>Alter rate of DNA transcription in nucleus </li></ul></ul><ul><ul><ul><li>Change patterns of protein synthesis </li></ul></ul></ul><ul><ul><li>Directly affect metabolic activity and structure of target cell </li></ul></ul><ul><ul><li>Includes steroids and thyroid hormones </li></ul></ul>:)
  27. 27. Mechanisms of Hormone Action <ul><li>Figure 18–4a Effects of Intracellular Hormone Binding. </li></ul>:)
  28. 28. Mechanisms of Hormone Action <ul><li>Figure 18–4b Effects of Intracellular Hormone Binding. </li></ul>:)
  29. 29. Endocrine Reflexes <ul><li>Endocrine Reflexes </li></ul><ul><ul><li>Functional counterparts of neural reflexes </li></ul></ul><ul><ul><li>In most cases, controlled by negative feedback mechanisms </li></ul></ul><ul><ul><ul><li>Stimulus triggers production of hormone whose effects reduce intensity of the stimulus </li></ul></ul></ul>:)
  30. 30. Endocrine Reflexes <ul><li>Endocrine reflexes can be triggered by </li></ul><ul><ul><li>Humoral stimuli </li></ul></ul><ul><ul><ul><li>Changes in composition of extracellular fluid </li></ul></ul></ul><ul><ul><li>Hormonal stimuli </li></ul></ul><ul><ul><ul><li>Arrival or removal of specific hormone </li></ul></ul></ul><ul><ul><li>Neural stimuli </li></ul></ul><ul><ul><ul><li>Arrival of neurotransmitters at neuroglandular junctions </li></ul></ul></ul>:)
  31. 31. Endocrine Reflexes <ul><li>Simple Endocrine Reflex </li></ul><ul><ul><li>Involves only one hormone </li></ul></ul><ul><ul><li>Controls hormone secretion by the heart, pancreas, parathyroid gland, and digestive tract </li></ul></ul><ul><li>Complex Endocrine Reflex </li></ul><ul><ul><li>Involves </li></ul></ul><ul><ul><ul><li>One or more intermediary steps </li></ul></ul></ul><ul><ul><ul><li>Two or more hormones </li></ul></ul></ul><ul><ul><ul><li>The hypothalamus </li></ul></ul></ul>:)
  32. 32. Endocrine Reflexes <ul><li>Figure 18–5 Three Mechanisms of Hypothalamic Control over Endocrine Function. </li></ul>:)
  33. 33. Endocrine Reflexes <ul><li>Neuroendocrine Reflexes </li></ul><ul><ul><li>Pathways include both neural and endocrine components </li></ul></ul><ul><li>Complex Commands </li></ul><ul><ul><li>Issued by changing </li></ul></ul><ul><ul><ul><li>Amount of hormone secreted </li></ul></ul></ul><ul><ul><ul><li>Pattern of hormone release: </li></ul></ul></ul><ul><ul><ul><ul><li>hypothalamic and pituitary hormones released in sudden bursts </li></ul></ul></ul></ul><ul><ul><ul><ul><li>frequency changes response of target cells </li></ul></ul></ul></ul>:)
  34. 34. The Pituitary Gland <ul><li>Also called hypophysis </li></ul><ul><li>Lies within sella turcica </li></ul><ul><ul><li>Diaphragma sellae </li></ul></ul><ul><ul><ul><li>A dural sheet that locks pituitary in position </li></ul></ul></ul><ul><ul><ul><li>Isolates it from cranial cavity </li></ul></ul></ul><ul><li>Hangs inferior to hypothalamus </li></ul><ul><ul><li>Connected by infundibulum </li></ul></ul>:)
  35. 35. Pituitary Gland <ul><li>Releases nine important peptide hormones </li></ul><ul><li>Hormones bind to membrane receptors </li></ul><ul><ul><li>Use cAMP as second messenger </li></ul></ul>:)
  36. 36. Pituitary Gland <ul><li>Figure 18–6a The Anatomy and Orientation of the Pituitary Gland. </li></ul>:)
  37. 37. Pituitary Gland <ul><li>Figure 18–6b The Anatomy and Orientation of the Pituitary Gland. </li></ul>:)
  38. 38. Pituitary Gland <ul><li>Median Eminence </li></ul><ul><ul><li>Swelling near attachment of infundibulum </li></ul></ul><ul><ul><li>Where hypothalamic neurons release regulatory factors </li></ul></ul><ul><ul><ul><li>Into interstitial fluids </li></ul></ul></ul><ul><ul><ul><li>Through fenestrated capillaries </li></ul></ul></ul>:)
  39. 39. Pituitary Gland <ul><li>Portal Vessels </li></ul><ul><ul><li>Blood vessels link two capillary networks </li></ul></ul><ul><ul><li>Entire complex is portal system </li></ul></ul><ul><ul><ul><li>Ensures that regulatory factors reach intended target cells before entering general circulation </li></ul></ul></ul>:)
  40. 40. Pituitary Gland <ul><li>Figure 18–7 The Hypophyseal Portal System and the Blood Supply to the Pituitary Gland. </li></ul>:)
  41. 41. Pituitary Gland <ul><li>Two Classes of Hypothalamic Regulatory Hormones </li></ul><ul><ul><li>Releasing hormones (RH) </li></ul></ul><ul><ul><ul><li>Stimulate synthesis and secretion of one or more hormones at anterior lobe </li></ul></ul></ul><ul><ul><li>Inhibiting hormones (IH) </li></ul></ul><ul><ul><ul><li>Prevent synthesis and secretion of hormones from the anterior lobe </li></ul></ul></ul><ul><li>Rate of secretion is controlled by negative feedback </li></ul>:)
  42. 42. Pituitary Gland <ul><li>Anterior lobe (also called adenohypophysis ) </li></ul><ul><ul><li>Hormones “turn on” endocrine glands or support other organs </li></ul></ul><ul><ul><li>Can be subdivided into three regions: </li></ul></ul><ul><ul><ul><li>Pars distalis </li></ul></ul></ul><ul><ul><ul><li>Pars intermedia </li></ul></ul></ul><ul><ul><ul><li>Pars tuberalis </li></ul></ul></ul>:)
  43. 43. Pituitary Gland <ul><li>Figure 18–8a Feedback Control of Endocrine Secretion </li></ul>:)
  44. 44. Pituitary Gland <ul><li>Figure 18–8b Feedback Control of Endocrine Secretion. </li></ul>:)
  45. 45. Pituitary Gland <ul><li>Figure 18–9 Pituitary Hormones and Their Targets. </li></ul>:)
  46. 46. Pituitary Gland :)
  47. 47. Pituitary Gland <ul><li>Posterior lobe (also called neurohypophysis) </li></ul><ul><ul><li>Contains unmyelinated axons of hypothalamic neurons </li></ul></ul><ul><ul><li>Supraoptic and paraventricular nuclei manufacture </li></ul></ul><ul><ul><ul><li>Antidiuretic hormone (ADH) </li></ul></ul></ul><ul><ul><ul><li>Oxytocin (OXT) </li></ul></ul></ul>:)
  48. 48. Pituitary Gland <ul><li>Figure 18–9 Pituitary Hormones and Their Targets. </li></ul>:)
  49. 49. Pituitary Gland :)
  50. 50. The Thyroid Gland <ul><li>Lies anterior to thyroid cartilage of larynx </li></ul><ul><li>Consists of two lobes connected by narrow isthmus </li></ul><ul><ul><li>Thyroid follicles </li></ul></ul><ul><ul><ul><li>Hollow spheres lined by cuboidal epithelium </li></ul></ul></ul><ul><ul><ul><li>Cells surround follicle cavity that contains viscous colloid </li></ul></ul></ul><ul><ul><ul><li>Surrounded by network of capillaries that </li></ul></ul></ul><ul><ul><ul><ul><li>deliver nutrients and regulatory hormones </li></ul></ul></ul></ul><ul><ul><ul><ul><li>accept secretory products and metabolic wastes </li></ul></ul></ul></ul>:)
  51. 51. The Thyroid Gland <ul><li>Thyroglobulin (Globular Protein) </li></ul><ul><ul><li>Synthesized by follicle cells </li></ul></ul><ul><ul><li>Secreted into colloid of thyroid follicles </li></ul></ul><ul><ul><li>Molecules contain the amino acid tyrosine </li></ul></ul><ul><li>Thyroxine (T 4 ) </li></ul><ul><ul><li>Also called tetraiodothyronine </li></ul></ul><ul><ul><li>Contains four iodide ions </li></ul></ul><ul><li>Triiodothyronine (T 3 ) </li></ul><ul><ul><li>Contains three iodide ions </li></ul></ul>:)
  52. 52. The Thyroid Gland <ul><li>Figure 18–10a The Thyroid Gland. </li></ul>:)
  53. 53. The Thyroid Gland <ul><li>Figure 18–10b-c The Thyroid Gland. </li></ul>:)
  54. 54. The Thyroid Gland <ul><li>Figure 18–11a The Thyroid Follicles: Synthesis, Storage, and Secretion of Thyroid Hormones. </li></ul>:)
  55. 55. The Thyroid Gland <ul><li>Figure 18–11b The Thyroid Follicles: The Regulation of Thyroid Secretion. </li></ul>:)
  56. 56. The Thyroid Gland <ul><li>Thyroid-Stimulating Hormone (TSH) </li></ul><ul><ul><li>Absence causes thyroid follicles to become inactive </li></ul></ul><ul><ul><ul><li>Neither synthesis nor secretion occurs </li></ul></ul></ul><ul><ul><li>Binds to membrane receptors </li></ul></ul><ul><ul><li>Activates key enzymes in thyroid hormone production </li></ul></ul>:)
  57. 57. The Thyroid Gland <ul><li>Thyroid Hormones </li></ul><ul><ul><li>Enter target cells by transport system </li></ul></ul><ul><ul><li>Affect most cells in body </li></ul></ul><ul><ul><li>Bind to receptors in </li></ul></ul><ul><ul><ul><li>Cytoplasm </li></ul></ul></ul><ul><ul><ul><li>Surfaces of mitochondria </li></ul></ul></ul><ul><ul><ul><li>Nucleus </li></ul></ul></ul><ul><ul><li>In children, essential to normal development of </li></ul></ul><ul><ul><ul><li>Skeletal, muscular, and nervous systems </li></ul></ul></ul>:)
  58. 58. The Thyroid Gland <ul><li>Calorigenic Effect </li></ul><ul><ul><li>Cell consumes more energy resulting in increased heat generation </li></ul></ul><ul><ul><li>Is responsible for strong, immediate, and short-lived increase in rate of cellular metabolism </li></ul></ul>:)
  59. 59. The Thyroid Gland :)
  60. 60. The Thyroid Gland <ul><li>C (Clear) Cells of the Thyroid Gland </li></ul><ul><ul><li>Produce calcitonin (CT) </li></ul></ul><ul><ul><ul><li>Helps regulate concentrations of Ca 2+ in body fluids </li></ul></ul></ul>:)
  61. 61. Parathyroid Glands <ul><li>Embedded in posterior surface of thyroid gland </li></ul><ul><li>Parathyroid hormone (PTH) </li></ul><ul><ul><li>Produced by chief cells </li></ul></ul><ul><ul><li>In response to low concentrations of Ca 2+ </li></ul></ul>:) Figure 18–12
  62. 62. Parathyroid Glands <ul><li>Figure 18–12 The Parathyroid Glands. </li></ul>:)
  63. 63. Parathyroid Glands <ul><li>Four Effects of PTH </li></ul><ul><ul><li>It stimulates osteoclasts </li></ul></ul><ul><ul><ul><li>Accelerates mineral turnover and releases Ca 2+ from bone </li></ul></ul></ul><ul><ul><li>It inhibits osteoblasts </li></ul></ul><ul><ul><ul><li>Reduces rate of calcium deposition in bone </li></ul></ul></ul><ul><ul><li>It enhances reabsorption of Ca 2+ at kidneys, reducing urinary loss </li></ul></ul><ul><ul><li>It stimulates formation and secretion of calcitriol at kidneys </li></ul></ul><ul><ul><ul><li>Effects complement or enhance PTH </li></ul></ul></ul><ul><ul><ul><li>Enhances Ca 2+ , PO 4 3- absorption by digestive tract </li></ul></ul></ul>:) Figure 18–12
  64. 64. Parathyroid Glands <ul><li>Figure 18–13 The Homeostatic Regulation of Calcium Ion Concentrations. </li></ul>:)
  65. 65. Parathyroid Glands :)
  66. 66. Suprarenal (Adrenal) Glands <ul><li>Lie along superior border of each kidney </li></ul><ul><li>Subdivided into </li></ul><ul><ul><li>Superficial suprarenal cortex </li></ul></ul><ul><ul><ul><li>Stores lipids, especially cholesterol and fatty acids </li></ul></ul></ul><ul><ul><ul><li>Manufactures steroid hormones: adrenocortical steroids (corticosteroids) </li></ul></ul></ul><ul><ul><li>Inner suprarenal medulla </li></ul></ul><ul><ul><ul><li>Secretory activities controlled by sympathetic division of ANS </li></ul></ul></ul><ul><ul><ul><li>Produces epinephrine (adrenaline) and norepinephrine </li></ul></ul></ul><ul><ul><ul><li>Metabolic changes persist for several minutes </li></ul></ul></ul>:)
  67. 67. Suprarenal (Adrenal) Glands <ul><li>Suprarenal Cortex </li></ul><ul><ul><li>Subdivided into three regions: </li></ul></ul><ul><ul><ul><li>Zona glomerulosa </li></ul></ul></ul><ul><ul><ul><li>Zona fasciculata </li></ul></ul></ul><ul><ul><ul><li>Zona reticularis </li></ul></ul></ul>:)
  68. 68. Suprarenal Glands <ul><li>Zona Glomerulosa </li></ul><ul><ul><li>Outer region of suprarenal cortex </li></ul></ul><ul><ul><li>Produces mineralocorticoids </li></ul></ul><ul><ul><ul><li>For example, aldosterone: </li></ul></ul></ul><ul><ul><ul><ul><li>stimulates conservation of sodium ions and elimination of potassium ions </li></ul></ul></ul></ul><ul><ul><ul><ul><li>increases sensitivity of salt receptors in taste buds </li></ul></ul></ul></ul><ul><ul><ul><li>Secretion responds to: </li></ul></ul></ul><ul><ul><ul><ul><li>drop in blood Na + , blood volume, or blood pressure </li></ul></ul></ul></ul><ul><ul><ul><ul><li>rise in blood K + concentration </li></ul></ul></ul></ul>:)
  69. 69. Suprarenal Glands <ul><li>Zona Fasciculata </li></ul><ul><ul><li>Produces glucocorticoids </li></ul></ul><ul><ul><li>For example, cortisol (hydrocortisone) with corticosterone </li></ul></ul><ul><ul><ul><li>Liver converts cortisol to cortisone </li></ul></ul></ul><ul><ul><li>Secretion regulated by negative feedback </li></ul></ul><ul><ul><li>Has inhibitory effect on production of </li></ul></ul><ul><ul><ul><li>Corticotropin-releasing hormone (CRH) in hypothalamus </li></ul></ul></ul><ul><ul><ul><li>ACTH in adenohypophysis </li></ul></ul></ul>:)
  70. 70. Suprarenal Glands <ul><li>Zona Fasciculata (cont’d) </li></ul><ul><ul><li>Accelerates glucose synthesis and glycogen formation </li></ul></ul><ul><ul><li>Shows anti-inflammatory effects </li></ul></ul><ul><ul><ul><li>Inhibits activities of white blood cells and other components of immune system </li></ul></ul></ul>:)
  71. 71. Suprarenal Glands <ul><li>Zona Reticularis </li></ul><ul><ul><li>Network of endocrine cells </li></ul></ul><ul><ul><li>Forms narrow band bordering each suprarenal medulla </li></ul></ul><ul><ul><li>Produces androgens under stimulation by ACTH </li></ul></ul>:)
  72. 72. Suprarenal Glands <ul><li>Figure 18–14a The Suprarenal Gland. </li></ul>:)
  73. 73. Suprarenal Glands <ul><li>Figure 18–14b-c The Suprarenal Gland. </li></ul>:)
  74. 74. Suprarenal Glands <ul><li>Suprarenal Medulla </li></ul><ul><ul><li>Contains two types of secretory cells </li></ul></ul><ul><ul><ul><li>One produces epinephrine (adrenaline) </li></ul></ul></ul><ul><ul><ul><ul><li>75 to 80% of medullary secretions </li></ul></ul></ul></ul><ul><ul><ul><li>The other produces norepinephrine (noradrenaline) </li></ul></ul></ul><ul><ul><ul><ul><li>20 to 25% of medullary secretions </li></ul></ul></ul></ul>:)
  75. 75. Suprarenal Glands :)
  76. 76. Pineal Gland <ul><li>Lies in posterior portion of roof of third ventricle </li></ul><ul><li>Contains pinealocytes </li></ul><ul><ul><li>Synthesize hormone melatonin </li></ul></ul>:)
  77. 77. Pineal Gland <ul><li>Functions of Melatonin </li></ul><ul><ul><li>Inhibiting reproductive functions </li></ul></ul><ul><ul><li>Protecting against damage by free radicals </li></ul></ul><ul><ul><li>Setting circadian rhythms </li></ul></ul>:)
  78. 78. Pancreas <ul><li>Lies between </li></ul><ul><ul><li>Inferior border of stomach </li></ul></ul><ul><ul><li>And proximal portion of small intestine </li></ul></ul><ul><li>Contains exocrine and endocrine cells </li></ul>:)
  79. 79. Pancreas <ul><li>Endocrine Pancreas </li></ul><ul><ul><li>Consists of cells that form clusters known as pancreatic islets , or islets of Langerhans </li></ul></ul><ul><ul><ul><li>Alpha cells produce glucagon </li></ul></ul></ul><ul><ul><ul><li>Beta cells produce insulin </li></ul></ul></ul><ul><ul><ul><li>Delta cells produce peptide hormone identical to GH-IH </li></ul></ul></ul><ul><ul><ul><li>F cells secrete pancreatic polypeptide (PP) </li></ul></ul></ul>:)
  80. 80. Pancreas <ul><li>Figure 18–15 The Endocrine Pancreas </li></ul>:)
  81. 81. Pancreas <ul><li>Figure 18–15 The Endocrine Pancreas </li></ul>:)
  82. 82. Pancreas <ul><li>Blood Glucose Levels </li></ul><ul><ul><li>When levels rise </li></ul></ul><ul><ul><ul><li>Beta cells secrete insulin, stimulating transport of glucose across plasma membranes </li></ul></ul></ul><ul><ul><li>When levels decline </li></ul></ul><ul><ul><ul><li>Alpha cells release glucagon, stimulating glucose release by liver </li></ul></ul></ul>:)
  83. 83. Pancreas <ul><li>Figure 18–16 The Regulation of Blood Glucose Concentrations </li></ul>:)
  84. 84. Pancreas <ul><li>Insulin </li></ul><ul><ul><li>Is a peptide hormone released by beta cells </li></ul></ul><ul><ul><li>Affects target cells </li></ul></ul><ul><ul><ul><li>Accelerates glucose uptake </li></ul></ul></ul><ul><ul><ul><li>Accelerates glucose utilization and enhances ATP production </li></ul></ul></ul><ul><ul><ul><li>Stimulates glycogen formation </li></ul></ul></ul><ul><ul><ul><li>Stimulates amino acid absorption and protein synthesis </li></ul></ul></ul><ul><ul><ul><li>Stimulates triglyceride formation in adipose tissue </li></ul></ul></ul>:)
  85. 85. Pancreas <ul><li>Glucagon </li></ul><ul><ul><li>Released by alpha cells </li></ul></ul><ul><ul><li>Mobilizes energy reserves </li></ul></ul><ul><ul><li>Affects target cells </li></ul></ul><ul><ul><ul><li>Stimulates breakdown of glycogen in skeletal muscle and liver cells </li></ul></ul></ul><ul><ul><ul><li>Stimulates breakdown of triglycerides in adipose tissue </li></ul></ul></ul><ul><ul><ul><li>Stimulates production of glucose in liver </li></ul></ul></ul>:)
  86. 86. Pancreas :)
  87. 87. Pancreas :)
  88. 88. Endocrine Tissues of Other Systems <ul><li>Many organs of other body systems have secondary endocrine functions </li></ul><ul><ul><li>Intestines (digestive system) </li></ul></ul><ul><ul><li>Kidneys (urinary system) </li></ul></ul><ul><ul><li>Heart (cardiovascular system) </li></ul></ul><ul><ul><li>Thymus (lymphoid system and immunity) </li></ul></ul><ul><ul><li>Gonads (reproductive system) </li></ul></ul>:)
  89. 89. Endocrine Tissues of Other Systems <ul><li>Intestines </li></ul><ul><ul><li>Produce hormones important to coordination of digestive activities </li></ul></ul><ul><li>Kidneys </li></ul><ul><ul><li>Produce the hormones calcitriol and erythropoietin </li></ul></ul><ul><ul><li>Produce the enzyme renin </li></ul></ul>:)
  90. 90. Endocrine Tissues of Other Systems <ul><li>Figure 18–17a Endocrine Functions of the Kidneys: The Production of Calcitriol </li></ul>:)
  91. 91. Endocrine Tissues of Other Systems <ul><li>Figure 18–17b Endocrine Functions of the Kidneys: Overview of the Renin-angiotensin System </li></ul>:)
  92. 92. Endocrine Tissues of Other Systems <ul><li>Heart </li></ul><ul><ul><li>Produces natriuretic peptides ( ANP and BNP ) </li></ul></ul><ul><ul><ul><li>When blood volume becomes excessive </li></ul></ul></ul><ul><ul><ul><li>Action opposes angiotensin II </li></ul></ul></ul><ul><ul><ul><li>Resulting in reduction in blood volume and blood pressure </li></ul></ul></ul><ul><li>Thymus </li></ul><ul><ul><li>Produces thymosins (blend of thymic hormones) </li></ul></ul><ul><ul><ul><li>That help develop and maintain normal immune defenses </li></ul></ul></ul>:)
  93. 93. Endocrine Tissues of Other Systems :)
  94. 94. Endocrine Tissues of Other Systems <ul><li>Testes (Gonads) </li></ul><ul><ul><li>Produce androgens in interstitial cells </li></ul></ul><ul><ul><ul><li>Testosterone is the most important male hormone </li></ul></ul></ul><ul><ul><li>Secrete inhibin in nurse (sustentacular) cells </li></ul></ul><ul><ul><ul><li>Support differentiation and physical maturation of sperm </li></ul></ul></ul>:)
  95. 95. Endocrine Tissues of Other Systems <ul><li>Ovaries (Gonads) </li></ul><ul><ul><li>Produce estrogens </li></ul></ul><ul><ul><ul><li>Principle estrogen is estradiol </li></ul></ul></ul><ul><ul><li>After ovulation, follicle cells </li></ul></ul><ul><ul><ul><li>Reorganize into corpus luteum </li></ul></ul></ul><ul><ul><ul><li>Release estrogens and progestins , especially progesterone </li></ul></ul></ul>:)
  96. 96. Endocrine Tissues of Other Systems :)
  97. 97. Endocrine Tissues of Other Systems <ul><li>Adipose Tissue Secretions </li></ul><ul><ul><li>Leptin </li></ul></ul><ul><ul><ul><li>Feedback control for appetite </li></ul></ul></ul><ul><ul><ul><li>Controls normal levels of GnRH, gonadotropin synthesis </li></ul></ul></ul><ul><ul><li>Resistin </li></ul></ul><ul><ul><ul><li>Reduces insulin sensitivity </li></ul></ul></ul>:)
  98. 98. Hormone Interactions <ul><li>Antagonistic (opposing) effects </li></ul><ul><li>Synergistic (additive) effects </li></ul><ul><li>Permissive effects: one hormone is necessary for another to produce effect </li></ul><ul><li>Integrative effects: hormones produce different and complementary results </li></ul>:)
  99. 99. Hormone Interactions <ul><li>Hormones Important to Growth </li></ul><ul><ul><li>GH </li></ul></ul><ul><ul><li>Thyroid hormones </li></ul></ul><ul><ul><li>Insulin </li></ul></ul><ul><ul><li>PTH </li></ul></ul><ul><ul><li>Calcitriol </li></ul></ul><ul><ul><li>Reproductive hormones </li></ul></ul>:)
  100. 100. Hormone Interactions <ul><li>Growth Hormone (GH) </li></ul><ul><ul><li>In children </li></ul></ul><ul><ul><ul><li>Supports muscular and skeletal development </li></ul></ul></ul><ul><ul><li>In adults </li></ul></ul><ul><ul><ul><li>Maintains normal blood glucose concentrations </li></ul></ul></ul><ul><ul><ul><li>Mobilizes lipid reserves </li></ul></ul></ul>:)
  101. 101. Hormone Interactions <ul><li>Thyroid Hormones </li></ul><ul><ul><li>If absent during fetal development or for first year </li></ul></ul><ul><ul><ul><li>Nervous system fails to develop normally </li></ul></ul></ul><ul><ul><ul><li>Mental retardation results </li></ul></ul></ul><ul><ul><li>If T 4 concentrations decline before puberty </li></ul></ul><ul><ul><ul><li>Normal skeletal development will not continue </li></ul></ul></ul>:)
  102. 102. Hormone Interactions <ul><li>Insulin </li></ul><ul><ul><li>Allows passage of glucose and amino acids across plasma membranes </li></ul></ul><ul><li>Parathyroid Hormone (PTH) and Calcitriol </li></ul><ul><ul><li>Promote absorption of calcium salts for deposition in bone </li></ul></ul><ul><ul><li>Inadequate levels causes weak and flexible bones </li></ul></ul>:)
  103. 103. Hormone Interactions <ul><li>Reproductive Hormones </li></ul><ul><ul><li>Androgens in males, estrogens in females </li></ul></ul><ul><ul><li>Stimulate cell growth and differentiation in target tissues </li></ul></ul><ul><ul><li>Produce gender-related differences in </li></ul></ul><ul><ul><ul><li>Skeletal proportions </li></ul></ul></ul><ul><ul><ul><li>Secondary sex characteristics </li></ul></ul></ul>:)
  104. 104. Hormone Interactions :)
  105. 105. Hormone Interactions :)
  106. 106. Hormone Interactions <ul><li>General Adaptation Syndrome (GAS) </li></ul><ul><ul><li>Also called stress response </li></ul></ul><ul><ul><li>How body responds to stress-causing factors </li></ul></ul><ul><ul><li>Is divided into three phases: </li></ul></ul><ul><ul><ul><li>Alarm phase </li></ul></ul></ul><ul><ul><ul><li>Resistance phase </li></ul></ul></ul><ul><ul><ul><li>Exhaustion phase </li></ul></ul></ul>:) Figure 18–18
  107. 107. Hormone Interactions <ul><li>Figure 18–18 The General Adaptation Syndrome. </li></ul>:)
  108. 108. Hormone Interactions <ul><li>Figure 18–18 The General Adaptation Syndrome. </li></ul>:)
  109. 109. Hormone Interactions <ul><li>Figure 18–18 The General Adaptation Syndrome. </li></ul>:)
  110. 110. Hormone Interactions <ul><li>Hormone Changes </li></ul><ul><ul><li>Can alter intellectual capabilities, memory, learning, and emotional states </li></ul></ul><ul><ul><li>Affect behavior when endocrine glands are over-secreting or under-secreting </li></ul></ul><ul><li>Aging </li></ul><ul><ul><li>Causes few functional changes </li></ul></ul><ul><ul><li>Decline in concentration of </li></ul></ul><ul><ul><ul><li>Growth hormone </li></ul></ul></ul><ul><ul><ul><li>Reproductive hormones </li></ul></ul></ul>:)
  111. 111. Hormone Interactions <ul><li>Figure 18–19 Functional Relationships between the Endocrine System and Other Systems </li></ul>:)
  112. 112. Hormone Interactions <ul><li>Figure 18–19 Functional Relationships between the Endocrine System and Other Systems </li></ul>:)
  113. 113. Hormone Interactions <ul><li>Figure 18–19 Functional Relationships between the Endocrine System and Other Systems </li></ul>:)