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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
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- 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]
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- 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"
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- 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)
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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
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- 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)
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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
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- 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
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dehydroepiandrosterone (DHEA)
made in the zona reticularis of the adrenal gland cortex and converted to estrogen or testosterone in the ovaries & testes
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- 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
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- chromaffin cellscells of the medulla that are derived from same neural crest cells that make sympathetic ganglia
- are essentially modified, axonless neurons
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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
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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
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- parathyroid gland: on the left
- thyroid gland: on the right
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- parafollicular cell stained for calcitonin
- light blue: follicular cells
- large white center: stored thyroglobulin colloid
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