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Endocrine2010
Question | Answer |
---|---|
Hypothalamus | – corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH), growth hormone-releasing hormone (GHRH), growth hormone-inhibiting hormone (somatostatin GHIH), prolactin-inhibiting hormone (PIH), melano |
mineralocorticoids | produced in zona glomerulosa of adrenal cortex & help control body’s Na & K content |
glucocorticoids, androgens, & estrogens | produced in zona fasciculate & zona reticularis; hormones produced & secreted by cortex called adrenal steroids/corticosteroids |
mineralocortocoids function | aldosterone maintains ECF volume, promotes sodium & water reabsorption & K excretion in the kidney tubules |
aldosterone secretion is regulated by | the renin-angiotensin system, serum K ion concentration, & ACTH |
renin-angiotensin system = | renin produced by renal arterioles, & its release is triggered by a decrease in ECF volume (can occur from blood loss, Na loss, posture changes) |
renin converts angiotensin I to angiotensin II (active form), which then stimulates the secretion of aldosterone, causing | the kidneys to reabsorb Na & water to bring the plasma volume & osmolarity back to normal |
aldosterone is also secreted when | serum K level increases above normal by as little as 0.1mEq/L |
glucocorticoids function: cortisol affects | carbs, protein, & fat metabolism, body’s response to stress, emotional stability, & immune function |
release of glucocorticoids is regulated by | ACTH from the AP & indirectly by the release of CRH from the hypothalamus (release of CRH & ACTH is affected by the serum level of free cortisol, sleep-wake cycle, & stress |
glucocorticoid release peaks in the morning & reaches lowest level | 12h after peak (emotional, chemical, or physical stress increases release of glucocorticoids) |
adrenal medullary hormones | (catecholamines) |
function: adrenal medulla secretes | norepinephrine (15%) & epinephrine (85%) |
norepinephrine acts mainly on | alpha-adrenergic receptors |
epinephrine most often stimulates | beta-adrenergic receptors |