TOB Endocrine II (18)

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TOB Endocrine II (18)
2013-11-01 00:25:57
Tissue Organ Biology

Exam 4
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    • Adrenal Glands (Suprarenal)
    • contain a cortex & a medulla surrounded by a dense CT capsule itself surrounded by a TON of fat
    • the arenal cortex has 3 different zones (dark -> light -> dark) all responsible for making different STEROID hormones
    • outer glomerulosa -> fasiculata -> inner reticularis
    • [you should be able to remember the adrenal gland makes steroid hormones cause it's surrounded by a capsule of FAT]
    • adrenal cortex cell
    • adrenal cortex CELLS tend to have a LOT of mitochondria and smooth ER (SER)
    • *features of a steroid-secreting cell
    • because steroid hormones are derived from cholesterol, they're first made in the mt --> SER for modification --> BACK to the mt for modification --> SER ready for secretion
    • "steroid synthesis ping pong"
    • zona glomerulosa (round ball)
    • clusters of cells look like round ball; will be sandwiched between CT capsule & zona fasiculata (clearer, much more fatty)
    • cells here makes mineralocorticoids (eg. aldosterone)
  1. aldosterone
    • hormone made my cells in the zona glomerulosa of the adrenal gland cortex that affects the distal convoluted tubule of the kidney
    • it increases sodium resorption & increases blood pressure (more Na causes more water to be reabsorbed into BV --> higher pressure)
    • aldosterone (therefore zona glomerulosa cells) are controlled by controlled by ACTH, Na+ & K+ levels, + angiotensin II
    • zona fasciculata (bundle)
    • gaps = fenestrated arteries
    • can see chords of cells, with clear splotches inside (extracted lipid droplets)
    • lighter staining (clearer, much more fatty)
    • cells here make glucocorticoids (cortisol)
  2. cortisol
    • hormone made my cells in the zona fasciculata of the adrenal gland cortex which up-regulates glucose metabolism (gluconeogenesis), decreases inflammatory by down regulating IL-2
    • it's release is stimulated by ACTH from the corticotrophs in the anterior pituitary
    • zona reticularis (net)
    • see a 3D network of anastomosing cords
    • cells here make androgens (gonadocorticoids): precursors for sex hormones
    • their production is controlled by ACTH from the corticotrophs in the anterior pituitary
  3. dehydroepiandrosterone (DHEA)
    made in the zona reticularis of the adrenal gland cortex and converted to estrogen or testosterone in the ovaries & testes
    • adrenal medulla
    • contains chromaffin cells which synthesize noradrenaline (norepinephrine) & adrenaline (epinephrine)
    • noradrenaline: stains darker; granules are larger
    • adrenaline: stains lighter; most cells make this; smaller granules
    • chromaffin cellscells of the medulla that are derived from same neural crest cells that make sympathetic ganglia
    • are essentially modified, axonless neurons
  4. phenylethanolamine N-methyltransferase
    • enzyme in the medulla that converts norepinephrine to epinephrine
    • it's controlled by glucocorticoids made in the zona fasciculata
    • the medulla and cortex are for the most part TOTALLY separate except for this one overlapping element
  5. What orientation are smooth muscle bundles surrounding blood vessels (*veins) in the adrenal medulla in?
    • longitudinally
    • if you take a cross-section of a BV, the surrounding SM is oriented longitudinally in the tunica media
    • when the muscles contract the vein shortens, helping to release any product (adrenaline) into the general circulation
    • parathyroid gland: on the left
    • thyroid gland: on the right
    • parafollicular cell stained for calcitonin
    • light blue: follicular cells
    • large white center: stored thyroglobulin colloid