Endocrine system

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Endocrine system

  1. 2. Controls many body functions - exerts control by releasing special chemical substances into the blood called hormones - Hormones affect other endocrine glands or body systems Consists of several glands located in various parts of the body. 1.Pituitary gland
  2. 4. The Pituitary Gland is divided into 2 areas <ul><ul><li>Posterior Pituitary: </li></ul></ul><ul><ul><ul><li>oxytocin </li></ul></ul></ul><ul><ul><ul><li>antidiuretic hormone ( ADH ) </li></ul></ul></ul><ul><ul><li>Anterior Pituitary: </li></ul></ul><ul><ul><ul><li>thyroid-stimulating hormone ( TSH ) </li></ul></ul></ul><ul><ul><ul><li>growth hormone ( GH ) </li></ul></ul></ul><ul><ul><ul><li>adrenocorticotropin ( ACTH ) </li></ul></ul></ul><ul><ul><ul><li>follicle-stimulating hormone ( FSH ) </li></ul></ul></ul><ul><ul><ul><li>luteinizing hormone ( LH ) </li></ul></ul></ul><ul><ul><ul><li>prolactin </li></ul></ul></ul>
  3. 5. <ul><li>2. Thyroid Gland </li></ul><ul><ul><li>- lies in the anterior neck just below the larynyx. </li></ul></ul><ul><ul><li>- Two lobes, located on either side of the trachea, connected by a narrow band of tissue called the isthmus . </li></ul></ul><ul><ul><li>- Sacs inside the gland contain colloid </li></ul></ul><ul><ul><li>thyroxine ( T4 ) </li></ul></ul><ul><ul><li>triiodothyronine ( T3 ) </li></ul></ul><ul><ul><li>“ C” cells within the thyroid produce the hormone calcitonin . </li></ul></ul>
  4. 6. <ul><li>Calcitonin , when released, lowers the amount of calcium in the blood. </li></ul><ul><li>hypothyroidism, or Myxedema. </li></ul>hyperthyroidism, commonly called Graves’ disease. <ul><ul><li>Long term hyperthyroidism: </li></ul></ul><ul><ul><ul><li>Exopthalmos </li></ul></ul></ul><ul><ul><ul><ul><li>bulging of the eyeballs </li></ul></ul></ul></ul><ul><ul><ul><li>In severe cases - a medical emergency called t hyrotoxicosis can result. </li></ul></ul></ul>
  5. 7. <ul><li>3. Parathyroid Glands </li></ul><ul><ul><li>small, pea-shaped glands, located in the neck near the thyroid </li></ul></ul><ul><ul><li>usually 4 - number can vary </li></ul></ul><ul><ul><li>regulate the level of calcium in the body </li></ul></ul><ul><ul><li>produce parathyroid hormone -  level of calcium in blood </li></ul></ul><ul><ul><li>Hypocalcemia can result if parathyroids are removed or destroyed. </li></ul></ul>
  6. 8. 4. Pancreas <ul><li>Islets of Langerhans </li></ul><ul><ul><li>specialized tissues in which the endocrine functions of the pancreas occurs </li></ul></ul><ul><ul><li>include 3 types of cells: </li></ul></ul><ul><ul><ul><li>alpha (  ) </li></ul></ul></ul><ul><ul><ul><li>beta (  ) </li></ul></ul></ul><ul><ul><ul><li>delta (  ) </li></ul></ul></ul><ul><ul><li>each secretes an important hormone . </li></ul></ul>
  7. 9. Alpha (  ) cells release glucagon , essential for controlling blood glucose levels. When blood glucose levels fall,  cells  the amount of glucagon in the blood. Beta Cells (  ) release insulin (antagonistic to glucagon). Insulin  the rate at which various body cells take up glucose. Thus, insulin lowers the blood glucose level. Delta Cells (  ) produce somatostatin , which inhibits both glucagon and insulin.
  8. 10. <ul><li>5. Adrenal Glands </li></ul><ul><ul><li>2 small glands that sit atop both kidneys. </li></ul></ul><ul><ul><li>Each has 2 divisions, each with different functions. </li></ul></ul>Adrenal Medulla catecholamine hormones norepinephrine epinephrine <ul><li>Adrenal Cortex </li></ul><ul><li>steroid hormones </li></ul><ul><li>glucocorticoids mineralocorticoids </li></ul><ul><li>androgenic hormones </li></ul>
  9. 11. <ul><li>6. Gonads and Ovaries </li></ul><ul><ul><li>the endocrine glands associated with human reproduction. </li></ul></ul><ul><li>Ovaries: </li></ul><ul><ul><li>located in the abdominal cavity adjacent to the uterus. </li></ul></ul><ul><ul><li>Manufacture </li></ul></ul><ul><ul><ul><li>estrogen </li></ul></ul></ul><ul><ul><ul><li>protesterone </li></ul></ul></ul><ul><li>Testes: </li></ul><ul><ul><li>located in the scrotum </li></ul></ul><ul><ul><li>produce sperm for reproduction </li></ul></ul><ul><ul><li>Manufacture </li></ul></ul><ul><ul><li>Testosterone </li></ul></ul>
  10. 12. Hypothalamic Hormones/Factors Corticotropin releasing hormone (CRH)- ACTH Thyrotropin releasing hormone (TRH)- TSH Gonadotropin releasing Hormone (GnRH)- FSH,LH Prolactin release inhibiting hormone (PRIH)- Prolactin Prolactin releasing factor (PRF)- Prolactin
  11. 13. Growth hormone releasing hormone (GHRH)- GH Growth hormone releasing inhibiting Factor (GHRIF)- GH Malinocyte-stimulating hormone releasing factor (MSH-RF)- α , β & ᵞ -MSH MSH release inhibiting factor (MSH-RIF)- α , β & ᵞ -MSH
  12. 14. At cell membrane receptors a) Through alteration of intracellular cAMP concentration b) Through IP3/DAG pathway c) Tyrosin kinase pathway Adrenalin Glucagon TSH,FSH,LH,PTH ACTH Calcitonin Vesopressin(V 2 ) Vasopressin(V 1 ) Oxytocin Insulin Growth hormone Prolactin
  13. 15. Steroidal hormones Glucocorticoids Mineralocorticoids Androgens Estrogens Progestins At nuclear receptor Thyroid hormones
  14. 17. Stimuli which cause growth hormone release Fasting Hypoglycaemia Exercise Stress Gh secretion is ↓ by ↑ in plasma free fatty acids High dose of glucocorticoids β adrenergic agonist Gh secretion is ↑ by 5HT agonist α adrenergic agonist
  15. 18. Growth hormone inhibitors Somatostatin 14 amino acid Inhibit secretion of- GH TSH Prolactin Insulin Glucagon G.I secretions By pitutary By Pancreas
  16. 19. Synthetic octapeptide of somatostatin 40 times more potent Long acting Use Acromegaly Secretory diarrhoeas associated with carcinoids, AIDS, cancer chemotherapy

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