Endocrinology II


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  • AFP is also tested in human amniotic fluid; used to detect abnormalties such as tubal effects, spinabifida
  • Graves disease: autoimmi8ne, attack certain connective tissues
  • Also maybe from tumor in pituitary gland
  • Low ca causes the PT to release PTH. The osteoclasts of the bone release Ca and Ca is abosrbed from the kidney and Intestine. The increase of Ca in the blood
  • Endocrinology II

    1. 1. Endocrinology II: Axis and systems Advanced Physiology of Animals ANSC 3405                                                                                                                                                                                                                                                                                                                                                                                                                                                  
    2. 2. <ul><li>Endocrine glands/organs </li></ul><ul><li>Hormones of hypothalamus and pituitary </li></ul><ul><li>HPA axis and adrenals </li></ul><ul><li>Hypothalamic Pituitary Gonadals axis </li></ul><ul><li>Thyroid axis </li></ul><ul><li>Growth axis </li></ul><ul><li>Calcium homeostasis </li></ul>Outline
    3. 3. Endocrine Tissues Located at base of brain (Testis in Male) Adrenal Gland Ovary Kidney Pituitary Hypothalamus Thyroid Parathyroid
    4. 4. Long Loop Short Loop Open Loop (Figure 9-12) Endocrine Tissue Tissue 1 Tissue 2 Tissue 3 + + - - +
    5. 6. Hypothalamus-pituitary Pituitary Stalk Hypophyseal Portal Vessels Posterior Pituitary ( Neurohypophysis ) Hypothalamus Anterior Pituitary (Adenohypohysis) (STUDY Figure 9-15)
    6. 7. Hypothalamo-hypophyseal portal system <ul><li>Carries hypothalamic hormones specifically to the anterior pituitary without dilution in the systemic blood. </li></ul><ul><li>1. Allows rapid response </li></ul><ul><li>2. Little dilution of peptide hormones </li></ul><ul><li>3. Peptides have short 1/2 life </li></ul><ul><li>Specific hypothalamic nuclei secrete releasing or release </li></ul><ul><li>Receptors to inhibit/control release of pituitary hormones. </li></ul>
    7. 8. Neurosecretory cells of Posterior Pituitary <ul><li>Posterior pituitary gland does NOT have cells that produce/store hormones </li></ul><ul><li>Neurosecretory cells of hypothalamus release hormones </li></ul><ul><ul><li>Directly into Posterior pituitary </li></ul></ul><ul><ul><li>Which is rapidly released into systemic bloodstream </li></ul></ul><ul><ul><li>Rapid response </li></ul></ul>
    8. 9. <ul><li>Corticotropin releasing hormone (CRH) </li></ul><ul><li>Gonadotropin Releasing Hormone (GnRH) </li></ul><ul><li>Thyroid Releasing Hormone (TRH) </li></ul><ul><li>Growth Hormone Releasing Hormone (GHRH) </li></ul><ul><li>Oxytocin </li></ul><ul><li>Vasopressin (VP, AVP) </li></ul>Hypothalamic Hormones
    9. 10. Pituitary Gland Anterior Pituitary Posterior Pituitary
    10. 11. Anterior Pituitary Cell Types and Hormones <ul><li>Corticotrophs </li></ul><ul><li>- Adrenalcorticotrophic (ACTH) </li></ul><ul><li>Gonadotrophs </li></ul><ul><ul><li>Release Leutinizing Hormone (LH) and Follicle stimulating hormone (FSH) </li></ul></ul><ul><li>Thyrotrophs </li></ul><ul><ul><li>Thyroid Stimulating Hormone (TSH) </li></ul></ul><ul><li>Lactotrophs </li></ul><ul><ul><li>Release Prolactin </li></ul></ul><ul><li>Somatotrophs </li></ul><ul><ul><li>Release Growth Hormone (GH) </li></ul></ul>
    11. 12. Hypothalamopituitary adrenal (HPA) axis (Figure 9-40) Adrenals Kidney Posterior Pituitary Gland Hypothalamus Anterior Pituitary Gland ACTH Stress Circadian rhythm CRH (-) Glucocorticoids, Catecholamines, etc.. Glucocorticoids, Catecholamines, etc.. Muscle: Net loss of amino Acids (glucose) Liver: Deamination of proteins into amino acids, gluconeogenesis (glucose) Fat Cells: Free fatty acid mobilization Heart rate: Increased Immune system: altered
    12. 13. Adrenal Glands
    13. 14. Adrenals Zona Reticularis Sex steroids (androgens) Zona Fasciculata Glucocorticoids (Cortisol) Glucose homeostasis and many others Zona Glomerulosa Mineralocorticoids (Aldosterone) Na+, K+ and water homeostasis Medulla: “ Catecholamines” Epinephrine, Norepinephrine, dopamine CORTEX
    14. 15. Hypothalamic-Pituitary-Gonadal Axis (HPG): Males Sertoli cells Leydig cells Hypothalamus Anterior Pituitary GnRH (Figure 9-46) Inhibin - - - Seminferous tubules: (Spermatogenisis) Male characteristics Growth Behavior: Libido, aggression + + Testosterone Testosterone LH FSH +
    15. 16. Hypothalamus AP GnRH Hypothalamic-Pituitary-Gonadal Axis (HPG): Females LH surge Tonic LH Progesterone FSH LH (Figure 9-47) PGF2a Estrogens + Estrogen
    16. 17. Estrous cycle Menstrual cycle (STUDY Figure 9-48)
    17. 18. Female Hormones <ul><li>Estrogens </li></ul><ul><ul><li>Somatic growth </li></ul></ul><ul><ul><li>Mammary growth (after puberty) </li></ul></ul><ul><ul><li>Reproductive organs </li></ul></ul><ul><li>Progesterones </li></ul><ul><ul><li>Mammary tissue growth (after fertilization) </li></ul></ul><ul><ul><li>Reproductive organs: Uterus lining </li></ul></ul><ul><ul><li>Maintain corpus luteum </li></ul></ul><ul><ul><li>PGF2 α from uterus causes regression of corpous luteum </li></ul></ul>
    18. 19. Mammary Function <ul><li>Oxytocin </li></ul><ul><ul><li>Smooth Muscle contraction </li></ul></ul><ul><ul><li>During birth </li></ul></ul><ul><ul><li>Causes contraction of myoepithelial cells, allowing milk ejection </li></ul></ul><ul><ul><li>Increases after cervical distention and suckling </li></ul></ul><ul><ul><li>High progesterone inhibits </li></ul></ul><ul><li>Prolactin </li></ul><ul><ul><li>Synthesis of milk proteins </li></ul></ul><ul><ul><li>Growth of mammary glands </li></ul></ul><ul><ul><li>Dopamine and PIH inhibits </li></ul></ul><ul><ul><li>Increased estrogen and low PIH causes increase </li></ul></ul>
    19. 20. Oxytocin Calf Stimulation of Mammary Gland Spinal Cord Neural Pathway to Hypothalamus Hypothalamus Posterior Pituitary Capillaries Oxytocin Release in Blood
    20. 21. Gender Developmental Hormones <ul><li>Testosterone </li></ul><ul><ul><li>Testosterone does not make the brain masculine </li></ul></ul><ul><ul><li>Testosterone is converted into estrogen (aromatase) in the brain, and estrogen makes the brain masculine </li></ul></ul><ul><li>Alpha Feto Protein </li></ul><ul><ul><li>In females, AFP binds to the estrogen, preventing estrogen from entering the brain </li></ul></ul><ul><ul><li>If a female animal lacks this AFP, or if estrogen levels are synthetically too high, then a female may develop a masculine brain </li></ul></ul>
    21. 22. <ul><li>AVP in males </li></ul><ul><ul><li>male aggression, mating persistence, territoriality, jealousy </li></ul></ul><ul><li>Oxytocin in females </li></ul><ul><ul><li>sexual arousal/receptivity and satiety, bonding, nurturing behaviors, social memories </li></ul></ul><ul><ul><li>  males and females release oxytocin and opioids during copulation which reduces aggression and facilitates social bonding </li></ul></ul>Gender and Hormones
    22. 23. Hypothalamothyroid axis <ul><li>Tissues become sensitive to epinephrine </li></ul><ul><li>Increase cellular respiration, O2 use and metabolism </li></ul><ul><li>Heat is generated </li></ul><ul><li>Thermoregulation </li></ul><ul><li>Growth and developement </li></ul>(Figure 9-42)
    23. 24. Thyroid Hormones <ul><li>Thyroxine (T 4 ) and 3,5,3-triiodothyronine (T 3 ) </li></ul><ul><ul><li>Formed from 2 iodinnated tyrosines precursers </li></ul></ul><ul><ul><li>Lipd soluble </li></ul></ul>
    24. 25. Thyroid diseases <ul><li>Hypothyroidism </li></ul><ul><ul><li>From low iodine during development causes severe retardation in growth (cretinism) </li></ul></ul><ul><ul><li>TSH increases, causing hypertrophy of gland (goiter) </li></ul></ul><ul><ul><li>Other forms cause obesity, thinning of hair and skin and lethargy, and feeling coldness </li></ul></ul>
    25. 26. Thyroid Diseases <ul><li>Hyperthyroidism </li></ul><ul><ul><li>Overactive thyroid (ex. Graves disease) </li></ul></ul><ul><ul><li>T 3 and T 4 over secretion </li></ul></ul><ul><ul><li>Propotosis, weight loss, hair loss, hot flashes, mood swings </li></ul></ul>
    26. 27. <ul><li>Insulin </li></ul><ul><ul><li>β cells secrete due to high blood glucose levels </li></ul></ul><ul><ul><li>Glucose uptake into tissues increases </li></ul></ul><ul><li>Glucagon </li></ul><ul><ul><li>α cells secrete when blood glucose is low </li></ul></ul><ul><ul><li>Glucose is released from tissues back into blood </li></ul></ul>Pancreatic axis (Figure 9-43)
    27. 28. Diabetes mellitus <ul><li>Type I </li></ul><ul><ul><li>“ Childhood” diabetes </li></ul></ul><ul><ul><li>Loss of pancreatic β cells </li></ul></ul><ul><ul><li>Decreased insulin </li></ul></ul><ul><li>Type II </li></ul><ul><ul><li>“ Adult” diabetes </li></ul></ul><ul><ul><li>Defective signal reception in insulin pathway </li></ul></ul><ul><ul><li>Decreased insulin </li></ul></ul><ul><li>Both cause hyperglycemia, glycosuria, lipid breakdown because tissues are deficient in glucose, ketone bodies </li></ul>
    28. 29. Growth hormone <ul><li>Control of GH </li></ul><ul><ul><li>Stress, exercise nutrition, sleep </li></ul></ul><ul><ul><li>Somatostatin (SS) inhibits </li></ul></ul><ul><ul><li>GH causes inhibition of glucose uptake and utilization, increased a.a. uptake and protein synthesis </li></ul></ul>(Figure 9-44)
    29. 30. Growth Hormones <ul><li>Action of several hormones. </li></ul><ul><li>GH primary job is to stimulate the liver </li></ul><ul><ul><li>To secrete IGF-1 (Insulin Growth Factor) </li></ul></ul><ul><li>IGF-1 </li></ul><ul><ul><li>stimulates proliferation of chondrocytes (cartilage cells), resulting in bone growth. </li></ul></ul><ul><ul><li>differentiation and proliferation of myoblasts </li></ul></ul><ul><ul><li>Stimulates amino acid uptake and protein synthesis in muscle and other tissues. </li></ul></ul>
    30. 31. Giantism <ul><li>Excessive GH durining childhood </li></ul><ul><li>Growth plate stimulation </li></ul><ul><li>Tumor of somatotrophs </li></ul>Robert Wardlow 8’ 11”.
    31. 32. <ul><li>GH late in life </li></ul><ul><li>Causes excessive growth of flat bones </li></ul>Acromegaly Rondo Hatton
    32. 33. Calcium Homeostasis <ul><li>Parathyroid </li></ul><ul><ul><li>most important endocrine regulator of calcium and phosphorus concentration in extracellular fluid (PTH) </li></ul></ul><ul><ul><li>Targets receptors on bones and kidneys </li></ul></ul><ul><li>Calcitonin </li></ul><ul><ul><li>C cells of Thymus </li></ul></ul><ul><ul><li>Decreases mobilization </li></ul></ul><ul><ul><li>and uptake of calcium </li></ul></ul>Study Figure 9.45
    33. 34. Calcium Homeostasis (Figure 9-45)
    34. 35. Calcium Homeostasis Parathyroid “ C” Cells PTH Calcitonin Bone Kidney Intestine Bone Kidney [Ca ++ ] [Ca ++ ] Stimulate Stimulate Inhibit Inhibit In plasma In plasma
    35. 36. More endocrine fun to come!
    36. 37. Look at those Tables <ul><li>Learn, Think, understand. </li></ul><ul><li>Don’t just memorize! </li></ul>