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  1. Describe the Adrenal blood supply:

    Venous drainage:
    • Superiorly - branches from inferior phrenic artery
    • Middle - aorta
    • Inferorly - branches from renal artery

    • Left adrenal vein + inferior phrenic vein ---> left renal vein
    • Right adrenal vein -> inferior vena cava

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  2. What enzyme converts norepinephrine to epinephrine?
    Phenylethanolamine-N-methyltransferase (PNMT)
  3. What is the rate limiting enzyme of catecholamine synthesis?
    Tyrosine hydroxylase
  4. Describe the catecholamine synthesis pathway:
    • 1.  L-tyrosine converted into dihydroxyphenylalanine (L-dopa) by tyrosine hydroxylase
    • 2.  L-dopa converted into dopamine by dopa decarboxylase
    • 3.  Dopamine converted into norepinephrine by dopamine β-hydroxylase
    • 4.  Norepinephrine converted into epinephrine by PNMT
  5. Describe the layers of the adrenal gland and their products:
    Image Upload 2

    • Adrenal Cortex (derived from mesoderm)
    • zona glomerulosa - mineralcorticosteroids (aldosterone)
    • zona fasiculata - corticosteroids
    • zona reticularis - sex steroids

    • Medulla (derived from ectodermal neural crest cells)
    • composed of chromaffin cells, innervated by sympathetic fibers from the sympathetic chain - secrete norepinephrine & epinephrine (NE -->Epi by PNMT found only in adrenal medulla)
  6. Secretion of Aldosterone controlled by:
    • Increased by:
    • Potassium - increases transcription of aldosterone synthase (CYP11B2)
    • Angiotensin II - increases transcription of aldosterone synthase (CYP11B2)
    • Adrenocorticotropic hormone (ACTH) - stimulates earlier pathways of adrenal steroidogenesis, increases aldosterone secretion modestly (by 10-20% over baseline)

    • Inhibited by:
    • Heparin
    • Somatostatin
    • Dopamine
    • Atrial natriuretic factor
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