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17 Cards in this Set
- Front
- Back
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hormones
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chemical messengers that transport signals from one cell to another
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4 major chemical classes of hormones:
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steroid, peptide, amino acid derivatives, prostaglandins and related compounds
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3 major functional types of hormones
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endocrine (steroid), paracrine (prostaglandins), autocrine (interleukin-2)
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common precursor and first step in steroid hormone synthesis
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cholesterol; degradation of side via desmolase and formation of pregnenolone (C21)
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what can happen to pregnenolone after formed from cholesterol
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(1) converted to progesterone which can be converted to gluco and mineral cortticoids (C21) in adrenal cortex, or (2) converted in many steps to testosterone (C19) --> aromatized to estradiol (C18)
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6 classes of steroid hormones
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glucocorticoids, mineral corticoids, androgens, estrogens, progestins, vitamin D
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3 layers of adrenal cortex
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outer zone - zona glomerulosa
middle zone - zona fasciculata inner zone - zona reticularis |
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zona glomerulosa
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outer zone of adrenal cortex, produces aldosterone (mineralcorticoid)
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zona fasciculata
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middle zone of adrenal cortex - produces cortisol (glucocorticoids)
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zona reticularis
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inner zone of adrenal cortex - produces corticosterone and adrogens
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Major functions of glucocorticoids
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increase gluconeogenesis and glycogenesis, increase protein catabolism, decrease Ab response, antiinflammatory and antineoplastic response
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major functions of mineralcorticoids
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increase sodium and water retention, promote potassium loss
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ACTH - adrenocorticotropic hormone
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single chain 39AA (MW 3500); produced by basophilic cells of adenohypophysis, 1-24-needed for full activity, 25-33-species differences and immunologic specificity, 34-39-seq. common to all species, half-life ~10mins, controlled by CRH-corticotropin releasing hormone from hypothalamus
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ACTH products
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used mainly for diagnostic purposes; limited therapeutic value in conditions responsive to corticosteroids;
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actions of ACTH on adrenal cortex
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decrease in adrenal: lipids, cholesterol, ascorbic acid; and increase in: adrenal weight, protein synthesis, oxidative phosphorylation and rate of glycolysis
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synthesis of glucocorticoids
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cholesterol--> pregnenolone --> 17-a-hydroxyprogesterone--> 11-deoxycortisol--> cortisol; requires hydroxylating enzymes
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synthesis of glucocorticoids
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cholesterol--> pregnenolone --> 17-a-hydroxyprogesterone--> 11-deoxycortisol--> cortisol; requires hydroxylating enzymes
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