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60 Cards in this Set
- Front
- Back
general steps in hormone synthesis
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1. preprohormone synthesized in rER; 2. signal peptides cleaved--> prohormone transported to Golgi; 3. more cleavage in golgi and HORMONE then packaged in secretory granules
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amine hormones
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derivates of TYROSINE, include thyroid hormone, Epi, NE
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active form of G protein?
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ATP-bound to alpha subunit
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how does caffeine work?
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inhibits phosphodiesterase which degrades cAMP (get more cAMP)
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IP3 signalling mech
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hormone + R--> Gq --> PLC --> DAG and IP3 --> PKC
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which hormones of anterior pituitary most homologous to TSH?
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FSH, LH (identical alpah subunits)
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"children" of POMC
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ACTH, MSH, beta-lipotropin, beta-endorphin
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which hormone of anterior pituitary most related to GH?
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prolactin
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what increases the pulsatile secretion of GH?
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sleep, stress, puberty, starvation, exercise, hypoglycemia
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what decreases GH secretion?
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somatostatin, somatomedins, obesity, hyperglycemia, preggers
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what does GH do in liver?
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causes production of somatomedins (insulin-life growth factors)
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4 direct actions of GH
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1. dec'd glucose uptake into cells; 2. inc'd lipolysis; 3. inc'd protein synthesis in mm; 4. inc'd production of IGF
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actions of GH via IGF
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inc'd protein synthesis! In chondrocytes--> growth spurt; in mm-->inc'd lean body mass; inc'd organ size
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how is prolactin secretion regulated?
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tonic inhibition by dopamine (which is stimulated by PRL); TRH increases PRL secretion
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4 actions of PRL
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1. stim milk production; 2. stim breast development (w/estrogen); 3. inhibits ovulation via GnRH inhibition; 4. inhibits spermatogenesis
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how treat PRL excess?
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bromocriptine (DA agonists)
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hormones of the posterior pituitary?
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ADH (supraoptic hypothal), oxytocin (paraventricular hypothal)
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what inhibits the iodide pump/trap in thyroid follicular epithelial cells?
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thiocyanate and perchlorate anions
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Wolff-Chaikoff effect?
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high levels of I- inhibit I- pump
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significance of propylthiouracil?
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inhibits peroxidase enzyme (which first catalyzes oxidation of I- to I2..and then other steps); used for treatment of hyperthyroidism
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what happens when TSh stimulates thyroid?
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iodinated thyroglobulin is taken back into follicular cells, digested and T3, T4 released into circulation. Leftover MIT, DIT deiodinated by thyroid deiodinase
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what happens to T3, T4 in circulation?
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mostly bound to TBG (inc'd in preggers); peripherally, T4-->T3 or rT3
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bone manifestation of thyroid deficiency?
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bone age < chronologic age, b/c TH stimulates bone maturations
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effect of TH on heart?
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upregulates beta 1 R
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effect of TH on O2 consumption?
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increases b/c of upregulation of Na-K ATPase (which uses ATP..which comes from O2..kinda)
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which part of adrenal cortex makes mineralocorticoids?
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(outermost) zona glomerulosa (works on kidneys..which have glomeruli)
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which part of adrenal cortex makes glucocorticoids?
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(middle) zona fasciculata
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which part of adrenal cortex makes androgens (DHEA, androstenedione)
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(innermost) zona reticularis (b/c you should be really particularis of your sex partners)
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effect of ACTH on adrenal cortex?
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stimulates cholesterol desmolase thereby increasing steroid synthesis; also upregulates own R
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control of aldosterone secretion?
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tonically--ACTH; also Ang II stimulates aldosterone synthase (corticosterone--> aldosterone)
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4 actions of glucocorticoids
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1. stim gluconeogenesis; 2. anti inflamm; 3. immunosuppressive; 4. upregulate alpha 1 R on arterioles
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how do glucocorticoids stimulate gluconeogenesis?
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1. increase protein catabolism in mm (more aa available); 2)decrease glucose utilization and insulin sensitivty of fat; 3) increase lipolysis (more glycerol available)
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how are glucocorticoids anti-inflammatory?
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induce synthesis of lipocortin (inhibits PLA2); inhibit production of IL-2, thereby inhibit proliferation of T cells; inhibit relase of His and serotonin from mast cells, platelets
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Name the dz: Increased ACTH, hypoglycemia, hyperpigmentation, ECF volume contraction
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Addison's disease
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how is secondary adrenocortical insufficiency different from Addison's?
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no hyperpigmentation; no volume contraxn ,hyperKalemia, metab acidosis
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Conn's syndrome leads to?
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HTN, hypokalemia, metab alkalosis, dec'd renin
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name the dz: decreased cortisol and aldosterone, increased adrenal androgens, virilization, suppression of gonad function
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21 hydroxylase deficiency
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name the dz: decreased androgen and glucocorticoid levels, increased aldosterone, hypoglycemia, lack of pubes
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17 hydroxylase deficiency
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3 major cell types and their main export in islets of Langerhans?
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alpha--glucagon; beta--insulin; delta--somatostatin, gastrin
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what do delta cells islets of Langerhans secrete?
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somatostatin, gastrin
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what stimulates glucagon release from alpha cells?
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decreased blood glucose
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3 actions of glucagon
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1. increase blood glucose; 2. increase blood FA, ketoacids; 3. increase urea production
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mechanism of insulin secretion?
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glucose binds GLUT 2 on beta cell membrane--> depolarization of membrane--> Ca channel opens, influx --> insulin secretion
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why get hyPOtension in uncontrolled DM?
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high [glucose] exceeds Tm in kidney so urine is very sugary-->osmotic diuretic
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what stimulates secretion of PTH?
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dec'd Ca; mildly dec'd Mg (severe hypoMg inhibits PTH secretion!)
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"goal" of PTH
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increase calcium, decrease phosphate
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4 actions of PTH
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1. increase bone reabsorp.; 2 inhibit renal phosphate reabsorp.(PCT); 3. increase renal Ca reabsorp.; 4. stimulate production of active vit D
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Albright's hereditary osteodystrophy
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pseudohypoparathyroidism cause by defective Gs in kideny and bone-->end organ resistance to PTH
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how does chronic renal failure lead to hypocalcemia?
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increased GFR--> increased sr phosphate which complexes with Calcium, thereby decreasing free Ca; also decreased vit D
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"goal" of vit D
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increase calcium and phosphate in ECF for bone mineralization
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Calcitonin: a) where b)stim'd by c)action
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a)parafollicular thyroid cells; b) increased sr Ca; c) inhibit bone reabsorp.
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what do Leydig cells make?
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testosterone
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why can't Leydig cells make glucocorticoids and mineralocorticoids?
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no 21 beta hydroxylase or 11 beta hydroxylase
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significance of 5 alpha reductase?
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enzyme that converts testosterone to DHT, found in accessory sex organs like the prostate
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significance of finasteride?
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inhibits 5alpha reductase (can tx BPH)
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FSH acts on Sertoli cells to?
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stimulate production of inhibin which has negative feedback effect on FSH
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what do theca cells make?
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androgens which are converted to estrogens by aromatase in granulosa cells
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2 causes of end organ ADH resistance
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1. drugs (Li!!! Inhibits Gs); 2. severe hypercalcemia (inhibits AC)
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which diuretics can also be used for treatment of acute mountain sickness?
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carbonic anhydrase inhibitors like acetazolamide (metabolic acidosis to combat respiratory alkalosis)
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why get HTN in 11beta hydroxylase deficiency?
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the precursor that the enzyme would act on is a weak mineralocorticoid
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