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23 Cards in this Set
- Front
- Back
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What are the three zones of the adrenal cortex?
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Zona Glomerulosa
Fasciclata Reticularis |
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What are the special cells of the adrenal medulla called?
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Chromaffin cells
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What arethe embryological origens of the chromaffin cells?
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Neural crest cells.
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name the hormones of the;
Adrenal cortex(from outer to inner zones) Adrenal medulla |
Mineralcorticoids-aldosterone
Glucocorticoids-cortisol Androgens-dehydroepiandrosterone(DHEA), androstenedione Catecholamines; epinephrine/norepinephrine |
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from what are the adrenocortical(steroid) hormones derived?
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Cholesterol
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What is special about the enzymes of the steroid hormone pathway?
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Most are members of the cytochrome P450 system.
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What is the rate limiting step in the synthetic pathway?
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Cholesterol desmolase
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How is the above step regulated?
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ACTH
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Name the actions of ACTH?
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1. increased activation of desmolase
2. increased cortisol synthesis 3. increased lipolysis 4. increased cholesterol uptake into adrenal cortex 5. increased proliferation of zona fasciculata. |
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List some actions of cortisol.
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1. increased hepatic gluconeogenesis
2. decreased protein syntheis 3. increased protein degradation 4.Facilitate interaction between PRL and insulin 5. Facilitate interaction between epi and NE and glucagon for normal metabolism. 6. decrease insulin 7. decrease immune/inflammatory response 8. decrease ACTH secretion |
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Name the actions of aldosterone.
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1. Increase sodium resorption in renal distal tubules
2. increase potassium and hydrogen excretion Net effect= increased volume |
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What factors regulate aldosterone synthesis?
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Renin-angiotensin 2-aldosterone system
2. increased K+ 3. Some control by ACTH |
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Describe the renin angiotensin 2 aldosterone pathway?
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Angiotensinogen---(renin)---angiotensin 1---(ACE)---angiotensin 2---aldosterone release.
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Which cells sense hypovolemia and release renin in response?
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Macula densa and juxtaglomerular cell.
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Where is ACE found?
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Lungs(major) and vasculature(minor)
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From what are the catecholamines derived?
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Tyrosine
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Briefly list the steps in the catecholamine pathway.
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Tyrosine---(tyrosine hydroxylase)---Dopa---(Dopa decarboxylase)---Dopamine---(Dopamine beta-hydroxylase)---Norepinephrine---(Phenylethanolamine-N-methytransferase)---Epinephrine
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How are the effects of Epi and Norepi mediated, and what are their second messenger systems?
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Via alpha and beta adrenergic receptors;
alpha1---intracellular calcium alpha2 receptor---decreases cAMP beta1 receptor---decreases cAMP beta2 receptor---decreases cAMP |
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What are the ocular effects of Epi/Norepi?
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Mydriasis(alpha1)
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What are the renal effects of epi/norepi?
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increased renin secretion(beta1)
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What are the half lives of Epi and norepi?
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App 2 minutes in circulation
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How are catecholamines metabolized/
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Nerve endings:
Norepinephrine---(MAO)---deaminated derivatives; Liver NE, Epi, deaminated derivatives---(catechol-O-methyltransferase(COMT)---Metanephrines---urine/Vanillylmandelic acid(VMA)---urine. |
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What are the percentages of catecholamine derivatives found in the urine?
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App-50% metanephrines
35% VMA(vanillylmandelic acid) |
