PHGY 210 endocrinology

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  1. aldosterone
    • mineralcorticoids.
    • increase Na absorption in the kidney, control blood pressure.
    • increase K and H loss via urination, maintain electrochemical balance.
  2. PTH
    • increase plasma Ca concentration. increase bone absorption, kidney absorption and Vit D synthesis. work with vit D to increase absorption of Ca in the gut.
    • 84 AA long, 34 AA at N-terminus essential for active parathyroid receptor.
    • hypo: tetany, muscle spasm (affect larynseal muscle, get asphaxiation). decrease vit D syn. Eat Vit D and Ca supplement.
    • Hyper: adenoma, form kidney stone. cardiac arrhythmias, decrease neural excitability, Ca deposits on blood vessel walls and bone cartilage. remove tumor and replacement therapy.
  3. Glucocorticoids function
    • 1. salt retention, aldosterone back up.
    • 2. protein and carb metabolism. increase gluconeogenic enzyme in liver, increase AA break down in muscle and adipose tissue. increase plasma glucose concentration.
    • 3. lipid metabolism, increase lipolytic enzymes in adipose cells. excess lead to hyperlipidemia and hypercholesterolemia. increase lipolytic action of other hormones.
    • 4. anti-inflammatory and immunosuppression, atropy of lympatic system, reduce antibody formation, decrease circulating lymphocytes. decrease histamine formation and allergy.
    • 5. bone, decrease protein matrix. osteroporosis.
  4. calcitonin
    • decrease plasma Ca concentration.
    • not essential for Ca homeostasis.
    • 32 AA all essential protein.
    • receptor in thyroid gland.
    • produced in C cells of thyroid glands.
    • increase bone deposition and decrease excretion by urine.
  5. Vitamin D
    • synthesis: 1. UVB + 7-dehydrocholesterol in skin. 2. 25-hydroxylation in liver. 3. 1-hydosylation in kidney (defective if renal disease).
    • synthesized from cholesterol, eat from cod liver oil and fatty fish.
    • function: increase plasma Ca concentration, part of immune system (antiinflammatory), anticancer.
    • low level: rickets (children), osteomalacia (adult).
  6. Difference between autocrine, paracrine and endocrine signaling.
    • autocrine: short distance, act on adjacent cell. 
    • paracrine: short distance, act on cell itself.
    • endocrine: long distance, act on different cell.
  7. Communication by hormones via six steps.
    • 1. synthesis (control amount of hormone).
    • 2. release (control timing of hormone action).
    • 3. transport (localize hormone, protein carrier).
    • 4. detection (specificity).
    • 5. change in metabolism (cascade, amplification).
    • 6. removal (half life, period/timing of hormone action).
  8. Classical endocrine organs.
    • 1. brain: hypothalamus, anterior pituitary.
    • 2. heart: atrial natriuretic peptides.
    • 3. thyroid, parathyroid glands.
    • 4. adrenal gland: cortex and medulla.
    • 5. ovary.
    • 6. testis.
    • 7. pancreas: islets of Langerhans.
  9. Classes of hormones.
    • 1. protein: christmas tree with decors.
    • 2. polypeptides: christmas tree.
    • 3. steroids: synthesized from cholesterol.
    • 4. amines: derived from tyrosine.
    • 5. ionic calcium: multiple function, ex. neurotransmitter.
  10. hypothalamic pituitary signaling.
    • from hypothalamus to anterior pituitary (hypothalamic hypophyseal portal system) via the blood vessels in the pituitary stalk.
    • 6 types of hormones in the anterior pituitary can be activated or inhibited.
  11. Aromatase
    • burn out methyl groups.
    • convert aldosterone to estradiol.
    • once methyl group comes off, spontaneous reaction involving carboxylation.
  12. rT3
    not a thyroid hormone.
  13. hormone receptor property and regulation.
    • Properties: specificity, affinity, saturability and measurable biological effect.
    • regulation: increase number of receptors or increase their sensitivity (amplitude of signaling).
  14. name two posterior pituitary hormones.
    • 1. vasopressin
    • 2. oxytocin
  15. name six anterior pituitary hormones. which one is not a peptide.
    • 1. thyrotropin-releasing hormone TRH
    • 2. gonadotropin-releasing hormone GnRH
    • 3. somatostatin
    • 4. growth hormone-releasing hormone GRH
    • 5. prolactin-inhibiting hormone PIH dopamine *
    • 6. corticotropin-releasing hormone CRH
  16. posterior pituitary gland
    • vasopressin and oxytocin are synthesized in two hypothalamic nuclei - supraoptic nucleus and paraventricular nucleus.
    • prohormones are processed in secretory granules during axonal transport.
    • mature hormones are liverated from neurophysins.
    • hormones are transported down the pituitary stalk.
  17. Contrast the effect of oxytocin in female and male.
    • female: parturition, uterus sensitive, cause dilation of uterus cervix and expulsion of fetus and placenta. milk ejection, stimulus is suckling.
    • male: ejaculation, assist epididymal passage of sperm.
    • similarities: behavioral effects, reduce anxiety, increase pro-social behaviours.
  18. thyroid gland.
    • 15-20g, 3g essential to be healthy.
    • has colloid, composed largely of thyroglobulin, surrounded by follicles.
    • T3 and T4 are split off from thyroglobulin.
    • synthesis of amines are under TSH control (pituitary).
    • thyroglobulin is a storage for T3 and T4.
  19. Deiodinase
    convert T4 to T3.
  20. thyroid hormone synthesis.
    • I2 + tyrosine in thyroglobulin -> MIT and DIT
    • MIT + DIT --> T3
    • DIT + DIT --> T4
    • process: oxidative coupling
    • TSH increases T3 and T4 rate limiting step.
  21. T3 and T4 regulation
    • TRH --> TSH --> T3 and T4 and negative feedback.
    • TSH act on receptors on the follicular cells.
  22. iodine deficiency.
    • non-toxic goiter.
    • no T3 and T4 produced, TRH and TSH production goes up but still no T3 and T4 are produced.
  23. effect of thyroid hormones. 4 in adults, 1 in children.
    • A. calorigenesis stimulation, increase cardiac output, oxygenation of blood, rate of breathing and RBCs.
    • B. carb metabolism, glycogen formation in liver, increase glucose uptake.
    • C. lipid turnover, increase lipid synthesis and oxidation.
    • D. protein metabolism, increase protein synthesis.
    • 1. normal growth, physical and neural development.
    • absence: irreversible mental retardation. stimulate syn of nerve growth factor NGF, induces dendritogenesis and regenaration of sympathetic neurons.
  24. T3 and T4 mechanism of action.
    • 1. diffuse into nucleus, find cognate receptor, alter transcription.
    • 2. interat with plasma memb and mito. not blocked by inhibitors of protein synthesis.
    • 3. act directly at plasma memb, increase AA uptake. indep of protein syn.
  25. hypothyroidism.
    • 1': myxedema. 4 causes: atrophy of the thyroid, autoimmune thyroiditis, goitrous hypothyroidism.
    • 2': little TSH
    • 3': little TRH.
    • infantile: no thyroid gland or no thyroid hormone syn at birth. bad physical growth and mental development. dwarfism and mental retardation associated with cretinism.
    • treatment: administer thyroid hormones.
  26. hyperthyroidism.
    • 1': toxic goiter, Grave's disease. 2 causes: Autoimmune, presence of Long Acting Thyroid Stimulator (LATS), mimic TSH. or thyroid adenoma/cancer, make T3 and T4 in absence of TSH stimulation.
    • 2': pituitary tumor, no -ve feedback.
    • 3': hypothalamic tumor, no -ve feedback.
    • treatment: surgery, eat radioactive iodide (5mCi), antithyroid drugs (propylthiouracil). replacement therapy, watch the dosage.
  27. 5 roles of Ca.
    • normal blood clotting
    • maintain transmemb potential of cells
    • excitability of nervous tissue
    • contraction of muscles
    • relase of hormones and neurotransmitter.
  28. conc of Ca and location
    • 10mg/1dL. 99% in bone, 50% bound, 50% free.
    • obtained from diet, especially diary.
  29. ACTH
    • adrenocorticotropin, 39 AA, syn as part of larger protein known as proopiomelanocortin (POMC).
    • disease: congenital adrenal hyperplasia, lack of cortisol because of lack of enzyme 11b-hydroxylase.
    • treatment: correct deficiency and normalize ACTH secretion.
    • bind to ACTH recept on memb of middle and lower layer.
    • cAMP cascade, activate steroidogenic enzyme, increase syn of steroid hormones.
    • diurnal rhythm.
    • indep of sleep and abolished by stress and Cushing's disease.
  30. Effect of stress of glucocorticoids.
    • increase the syn and release of CRH, ACTH and cortisol.
    • advantage: provide energy
    • disadvantage: cortisol inhibits wound healing
    • increase blood glucose (diabetes mellitus), decrease immune response, loss of bone.
  31. adrenal glands
    • cortex: lipid epithelial, from mesoderm. produce steroid hormones. glucocorticoids, mineralocorticoids, and progestins.
    • medulla: chromaffin cells, from neural crest. add potassium bichromate, become fine brown granules. catecholamine epinerphrine and norepinephrine and peptide hormones (enkephalins, dynorphins and atrial natriuretic peptides).
  32. adrenal cortex, 3 layers.
    • upper: mineralocorticoids.
    • middle: glucocorticoids.
    • lower: glucocorticoids, progestins, androgen and estrogens.
    • hypo: addison's. no adrenocortical hormones. atrophy of adrenal glands due to tubreculosis. treat with aldosterone.
    • hyper: cushing's. too much ACTH. too much glucocorticoids and mineralocorticoids. surgery. lead to osteoporosis.
  33. pancreas
    sevretes digestive enzymes.
Card Set:
PHGY 210 endocrinology
2014-01-21 19:44:59

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