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Endocrine physiology


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glandular functions

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Endocrine physiology

  2. 2. Overview of Endocrine System
  3. 3. Endocrine Glands and Hormones Endocrine glands produce hormones and secrete them into the bloodstream.  Ductless glands Hormones then travel through the bloodstream until they reach their target organ, which they affect in a highly specific manner.  Hormones only affect the organ(s) that contain a specific receptor for that hormone; resulting in this highly specific response once a hormone binds to its target tissue.
  4. 4. Feedback Control Mechanisms
  5. 5. Pituitary Gland Attached to the hypothalamus by the infundibulum Divided into two lobes:  Anterior Lobe  Glandular tissue  Posterior Lobe  Neural tissue
  6. 6. Anterior Pituitary 1 Hypothalamic neurons secrete releasing and inhibiting hormones into primary capillary plexus. 2 Hypothalamic hormones travel though hypophyseal portal veins to the anterior pituitary; where they stimulate or inhibit release of hormones from the anterior pituitary. 3 Anterior pituitary hormones are secreted into secondary capillaries.
  7. 7. Hypothalamic Control of Anterior Pituitary
  8. 8. Anterior Pituitary Hormones  Trophic hormones stimulate hormone secretion in other glands:  Growth Hormone (GH)  Thyroid-stimulating hormones (TSH)  Adrenocorticotropic hormone (ACTH)  Follicle-stimlulating hormone (FSH)  Luteinizing hormone(LH)  Prolactin (PRL)  Can cause hypertrophy of target organ at high concentrations.
  9. 9. Posterior Pituitary
  10. 10. Posterior Pituitary Hormones Anti-diuretic Hormone (ADH)  Also known as vasopressin  Acts upon kidney to promote water re-absorption  Urine volume is decreased Oxytocin  Stimulates smooth muscle contraction, especially during parturition (birthing process)  Promotes milk let-down (milk ejection reflex) in females.
  11. 11. Adrenal GlandAdrenal Cortex Regulated by hormones Release hormones called corticosteroids  Zona glomerulosa – secretes mineralcorticoids  Regulate Na+ and K+ balance  Aldosterone: Sodium and water retention; while excreting potassium  Zona fasciculata – secretes glucocorticoids  Regulate glucose metabolism and that of other organic molecules.  Cortisol: stimulate glucose formation and inhibit utilization of glucose.  Zona reticularis – secrete sex steroids  Weak androgens like Dehydropepiandrosterone (DHEA)Adrenal medulla  Regulated by neural innervation  Secretes epinephrine and norepinepherine  Cause sympathetic-like response  Activate by stress (fight or flight response) “Girls From Russia Make Good Soup”
  12. 12. Thyroid Gland
  13. 13. Goiter Formation Caused by hypothyroidism  Low-iodine intake; nutritional deficiency  Endemic goiter Caused by hyperthyroidism  Autoimmune response  Grave’s disease
  14. 14. Pancreas  The pancreas is both an endocrine and an exocrine gland.  Endocrine cells are located in islets of Langerhans.  Alpha cells secrete glucagon  Beta cells secrete insulin
  15. 15. This is what we will see in lab today
  16. 16. Figure 11.11
  17. 17. Figure 11.30
  18. 18. Diabetes Mellitus Type I Diabetes Mellitus [insulin-dependent]  “adolescent-onset diabetes”  Caused by destruction of the beta cells.  Lack of insulin secretion leads to extracellular hyperglycemia and increased lipolysis  Ketonemia  Diabetic ketoacidosis: a condition of insulin deficiency causing increased hepatic ketogenesis; occurs in Type I diabetes only.  10% of diabetic population Type II Diabetes Mellitus [non insulin-dependent]  “maturity-onset diabetes”  Insulin resistance (target cells do not respond normally)  Normal or elevated [insulin] initially; relative insulin deficiency  Most patients obese  90% of diabetic population
  19. 19. Oral Glucose Tolerance Test (OGTT)
  20. 20. Pineal Gland