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42 Cards in this Set
- Front
- Back
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What three things control the release of aldosterone from the adrenal cortex?
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renin-angiotensin; Potassium; ACTH (less degree)
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What zone fo the adrenal cortex is aldosterone released from?
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Zona glomerulosa
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What is the major function of aldosterone?
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controlling body fluid volume; by increasing the reabsorption of sodium
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Is aldosterone essential for life?
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Yes
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Is cortisol secretion able to compensate for the loss of aldosterone?
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No (even though high levels of cortisol excert a mineralcorticoid effect)
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What are the FIVE systems for fluid and electrolyte homeostasis?
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renin-angiotensin-aldosterone; ADH; Thirst; Sodium Apetite; Atrial natriuretic factor
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Where is the action site for aldosterone?
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Cells of the distal tubule of the kidney nephron, sweat glands, intestine and salivary glands
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Where are the receptors of aldosterone located (cytoplasm, surface membrane?)
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Cytoplasm >> It is a steroid hormone
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How long does it take to see the effects of aldosterone after cell penetration?
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30-60 mins (due to required protein synthesis to mediate effects)
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What are some of the proteins synthesized by aldosterone that increase sodium reabsorption?
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Sodium transporter (pump); and Enzymes that make energy for the pump
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What does Spironolactone do?
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Drug; Blocks aldosterone receptors
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The excretion of potassium induced by aldosterone is dependent upon what?
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Active reabsorption of sodium (the pump…no sodium = no potassium)
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What is the initial change in potassium blood levels following an intake of sodium (sodium load)?
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Blood levels will remain normal despite increased reabsorption of potassium (cells act as sponges for potassium)
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This complex secretes renin, and is located in the kidney?
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juxtaglomerular apparatus
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The action of this enzyme converts angiotensin 1 to angiotensin 2?
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ACE
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Where does ACE arise from (the enzyme)?
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plasma membranes of vascular endothelial cells throughout the body
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What is the juxtaglomerular apparatus directly innervated by (parasympathetics or sympathetics)?
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renal sympathetic neurons
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What is a major stimulus for renin secretion by the juxtaglomerular apparatus acting as a baroreceptor?
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Decreased perfusion pressure of the afferent arteriole
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What does the juxtaglomerular apparatus sense when acting as a chemoreceptor for the stimulus of renin?
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NaCl content in the distal tubule (macula densa)
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What does the sympathetic system and its innervation in the juxtaglomerular apparatus do when plasma blood volume decreases?
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stimulates the release of renin and subsequent conservation of sodium to increase blood pressure
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What zone of the adrenals does potassium directly act on?
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Zona glomerulosa (where aldosterone is)
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Potassium (increases or decreases ) the secretion of aldosterone?
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Increases
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What kind of role does ACTH have on the structure and function of the zona glomerulosa?
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Permissive (without it this zone atrophies)
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The clinical hallmarks of this disease are hypokalemia and hypertension?
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Primary aldosterone excess (adrenal tumor)
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What are some symptoms of hypokalemia?
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weakness and paralysis; metaboloc acidosis (H+ loss); Polyuria
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What are the three ionic changes that occur in the distal tubule as a result of aldosterone?
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Sodium absorption; Potassium secretion; Proton secretion
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What occurs to aldosterone secretion in patients with cirrhosis of the liver with ascites?
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"effective" decreased volume leads to increased renin-angiotensin and aldosterone increases
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Are androgens essential for life?
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No
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What are the physiological FUNCTION of androgens?
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Secondary sex characteristics in both males and females
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What can androgens contribute to in women?
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libido and sexual responsiveness
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What enzyme defieciency is responsible for congenital adrenal hyperplasia?
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21-hydroxylase defieciency
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True/False Patients with congenital adrenal hyperplasia have increased levels of cortisol and aldosterone?
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False; They have decreased levels of these two, everything is shuttled over to androgen
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Where does the adrenal medulla come from (embyological origin)?
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Neural crest Cells (postganglionic sympathetic neurons that morphed into secretory cells)
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One cell in the adrenal medulla contains this enzyme, needed to convert noepinephrine to epinephrine?
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PNMT - phenyl-N-methyl-transferase
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What hormone is needed for the conversion of noepinephrine to epinephrine (it helps the enzyme)?
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Cortisol ( this is why the blood flows from the cortex to the medulla)
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What is the difference between fetal stores of catecholamine producing cells (chromafin cells) and adult stores?
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Fetal stores are found in several extra-adrenal locations and are sensitive to a "non-mammalian" form of PNMT
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Where is 80% of the noepinephrine secreted from?
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sympathetic nerve terminals innervating vascular smooth muscle
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Where are 100% of the epinephrine secreted from?
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Adrenal medulla
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Circulating levels of (noepinephrine or epinephrine) reflect adrenal medullay secretion?
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epinephrine
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Can epinephrine and noepinephrine interact with both alpha and beta adrenergic receptors?
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Yes though with different affinities
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What is the rate limiting step for catecholamine synthesis?
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tyrosine hydroxylase
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What is a pheochromocytoma?
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a catecholamine secreting tumor
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