Endocrine Anatomy/Physiology

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  1. Zona glomerulosa (control by RAAS)
    Secretes aldosterone
  2. Zona Fasciculata (control by ACTH, hypothalamic CRH)
    Secretes cortisol, sex hormones
  3. Zona Reticularis (control by ACTH, hypothalamic CRH)
    Secretes sex hormones
  4. Medulla (regulated by preganglionic sympathetics)
    Secretes catecholamines from chromaffin cells (neural crest origin)
  5. Posterior Pituitary (neurohypophesis) - neuroectodermal origin
    Secretes ADH and Oxytocin, carried by neurophysins
  6. Anterior Pituitary (adenohypophesis) - derived from Rathke's Pouch (mesodermal?)
    • "Flat Pig"
    • *FSH
    • *LH
    • ACTH
    • *TTSH
    • Prolactin
    • GH
    • *share a-subunit (also hCG)
  7. Hormones that share same a-subunit
    FSH, LH, TSH, hCG
  8. Endocrine pancreas cell types
    • a = glucagon (periphery)
    • B = insulin (central)
    • delta = somatostatin (interspersed)
  9. Insulin: production
    B cell response to ATP from glucost metabolism

    Increased ATP -> closes K+ channel -> depolarizes cell -> increased of Ca2+ -> exocytosis of insulin
  10. Insulin: labs
    Serum C-peptide not present with exogenous intake
  11. GLUT-1
    RBCs and brain
  12. GLUT-2 (bidirectional)
    • Glucose transport in:
    • B islet cells
    • Liver
    • Kidney
    • Small intestine
  13. GLUT-4 (insulin-responsive)
    Glucose transport in: adipose tissue, skeletal muscle
  14. Insulin: actions
    • Increase glucose transport
    • Increase glycogen synthesis and storage
    • Increase TG synthesis and storage
    • Increase Na+ retention
    • increase protein synthesis
    • Increase cellular uptake of K+ and amino acids
  15. TRH stimulates release of:
    TSH, prolactin release stimulated by:
  16. Dopamine inhibits release of:
    Prolactin release inhibited by:
  17. CRH stimulates release of:
    ACTH release stimulated by:
  18. GHRH stimulates release of:
    GH release stimulated by:
  19. Somatostatin inhibits release of:
    GH, TSH release inhibited by:
  20. GnRH stimulates release of:
    FSH, LH release stimulated by
  21. Prolactin inhibits release of:
    GnRH release inhibited by
  22. Prolactin Regulation
    Secretion from anterior pituitary inhibited by dopamine from hypothalamus
  23. Prolactin self-regulation
    Inhibits own secretion by increasing dopamine synthesis / secretion
  24. Prolactin: function
    • Stimulates milk production in breast
    • Inhibits GNRH, thus:
    • Inhibits ovulation (in females)
    • Inhibits spermatogenesis (males)
  25. Bromocriptine
    • Dopamine agonist inhibiting prolactin secretion
    • Treats prolactinoma
  26. Dopamine antagonists (antipsychotics) and estrogens (OCPs, pregnancy)
    Medications that stimulate prolactin secretion
  27. 17a-hydroxylase deficiency: products
    • Decrease sex hormones
    • Decreased cortisol
    • Increased mineralocorticoids
  28. 17a-hydroxylase deficiency: Symptoms
    • HYPERtension (increased mineralcorticoids) -> hypokalemia
    • XY: decreased DHT -> pseudohermaphroditism
    • XX: externally phenotypic female w/ normal internal sex organs (no secondary sex characteristics)
  29. 21-hydroxylase deficiency: products
    • Decreased cortisol (increased ACTH)
    • Decreased MC
    • Increased sex hormones
  30. 21-hydroxylase deficiency: symptoms
    • Most common form
    • HYPOtension (decreased mineralcorticoids)
    • Masculinization
    • Female pseudohermaphroditism
    • Hyperkalemia
    • Increased plasma renin, volume depletion
    • Salt wasting
  31. 11B-hydroxylase deficiency
    • Decreased cortisol
    • Decreased aldosterone / corticosterone
    • Increased sex hormones
    • Sx: masculinization, HYPERtesnsion (increased 11-deoxycortocosterone - acts like aldosterone)
  32. Cortisol: function
    • BBIIG
    • Blood pressure (upregulates a1 receptors - works with epinephrine)
    • Bone formation (decreased)
    • antiInflammatory
    • Immune function (decreased)
    • Gluconeogensis, lipolysis, proteolysis
  33. Cortisol: Regulation
    • CRH -> ACTH
    • (cortisol feedsback on CRH, ACTH, cortisol secretion)
  34. Parathyroid: origin
    • 3rd pharyngeal pouch: Inferior parathyroid / Thymus
    • 4th pharyngeal pouch: Superior parathyroid
  35. PTH action on bone
    Stimulates osteoblasts -> increases production of M-CSF / RANK-L
  36. PTH regulation
    • Decreased Ca2+ INCREASES secretion
    • Decreased Mg2+ DECREASES secretion
  37. Vitamin D: Function
    • increase absorption of dietary Ca/P
    • Increase resorption of Ca2+ and PO4
  38. Regulation of Vitamin D
    • Increased production:
    • increased PTH
    • Decreased Ca2+
    • Decreased phosphate
    • Decreased production:
    • Vitamin D
  39. Calcitonin: source
    Parafollicular cells (C cells) of thyroid (neural crest origin?)
  40. Calcitonin: function
    Decreases bone resorption of calcium
  41. Calcitonin: regulation
    Increased serum Ca2+ causes secretion
  42. cAMP signaling pathways
    • FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2), MSH, PTH, calcitonin, GHRH, glucagon
  43. cGMP
    • vasodilators
    • ANP, NO (EDRF)
  44. IP3
    • GOAT
    • GnRH, Oxytocin, ADH (V1) TRH
  45. Cytosolic Steroid Receptors
    • VET CAP
    • Vit D, Estrogen, Testosterone, Cortisol, Aldosterone, Progesterone
  46. Nuclear Steroid Receptors
    T3 / T4 signaling pathway
  47. Intrinsic tyrosine kinase (MAP kinase) pathway
    Insulin, IFG-1, FGF, PDGF (growth factors)
  48. Receptor-associated tyrosine kinase pathway (JAK/STAT)
    GH, prolactin, IL-2
  49. T3 functions
    • Brain maturation
    • Bone growth
    • B-adrenergic effects
    • BMR increased
  50. Thyroxine-binding globulin
    • Binds most T3/T4
    • Decreased in hepatic failure
    • increased in pregnancy / OCP use (estrogen increases TBG)
  51. T4 vs T3
    • T4 is major product; converted to T3 by peripheral tissue
    • T3 has greater affinity
  52. T3/T4 synthesis
    • 1. Thyroglobulin (TG) made in follicular cell, pumped into lumen
    • 2. Iodine pumped into, oxidized and organified (peroxidase) -> I2 in lumen
    • 3. MIT and DIT (TG + I2) coupled to T3/T4 (peroxidase)
    • 4. Proteolyzed in follicular cell, free T3/T4 spit out on basolateral side into blood
Card Set:
Endocrine Anatomy/Physiology
2011-03-11 02:17:34
endocrine anatomy physiology

Endocrine Anatomy / Physiology
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