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33 Cards in this Set
- Front
- Back
Where is ADH secreted from?
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Posterior Pituitary
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What are the two functions of ADH?
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Increase peripheral vascular resistance and control reabsorption of molecules in the tubules of the kidneys.
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Where does ADH increase water absorption?
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Distal tubule & Collecting Duct
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How does ADH increase water absorption?
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Insertion of Aquaporin-2 into the apical membrane of the distal tubule
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On what receptors does ADH act?
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V2 - G protein-coupled receptors
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How does the insertion of Aquaporins by ADH occur?
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V2 receptors couple to Gs activating adenylyl cyclase, rise in cAMP triggers insertion.
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Other than insertion of aquaporins what other role does ADH play in the kidney?
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Increases permeability of inner medullary portion of collecting duct to urea allowing increase reabsorption of urea into the medullary interstitium.
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What effect does ADH have on the cardiovascular system?
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Increases peripheral vascular resistance and thus increases arterial blood pressure.
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When is ADH mediated increase in vascular resistance imporant?
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As a compensatory mechanism in hypovolemic shock eg during hemorrhage
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ADH is secreted from posterior pituitary in response to what three things?
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Reduction in plasma volume
Response to increase in plasma osmilality Response to cholecystokinin from small intestine |
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How is ADH secretion in response to reduced plasma volume mediated?
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Activated by baroreceptors (Carotid Sinus, Aortic Arch and low pressure receptors in veins, pulmonary vessels
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How is ADH secretion in response to increased plasma omsotic pressure mediated?
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Osmoreceptors in the hypothalamus
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What are the symptoms of decreased ADH release or decreased sensitivity to ADH?
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Diabetes insipidus -> hypernatremia, polyurua, polydipsia
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Where is angiotensinogen produced and released?
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The liver
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Where is renin produced?
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Kidneys - Granular cells of juxtaglomerular apparatus
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Name three stimuli increasing renin production in the kidney? Which cells detect these changes?
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Decrease in arterial blood pressure detected by baroreceptors.
Decrease in sodium chloride levels in ultra-filtrate of nephron measured by macula densa of juxtaglomerular apparatus. Sympathetic nervous system activity through beta1 adrenergic receptors |
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What exactly does renin do?
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Cleaves the peptide bond between leucine and valine residues on angiotensinogen creating angiotensin I/
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What biological activity does angiotensin I have?
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None, solely exists as precursor to angiotensin II.
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What enzyme converts angiotensin I to angiotensin II?
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Angiotensin-converting enzyme
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Where is angiotensin converting enzyme found?
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Predominantly in capillaries of the lung
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What does angiotensin II do overall?
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Increase blood pressure and blood volume.
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Name five specific effects of angiotensin II?
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1. Increase sympathetic activity
2. Increase secretion of aldostrone 3. Increase tubular Na+, Cl- reabsorption and K+ excretion causing water retention 4. Arteriolar vasoconstriction 5. Increased ADH secretion from posterior pituirary |
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What does aldosterone do?
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Increases reabsporption of sodium ions and water and release of potassium in the distal convoluted tubules.
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Where is aldosterone produced?
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Zona glomerulosa of adrenal cortex
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Where does aldosterone act?
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Distal tubules of nephron
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In what condition is aldosterone activity reduced?
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Addisons disease
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In what condition is aldosterone activity increased?
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Conn syndrome
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Name three factors stimulating aldosterone release:
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Plasma acidosis
Stretch receptors in atria of heart Increase in plasma angiotensin II |
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Name a renin inhibitor?
What is its mode of action? |
Aliskiren
It binds to the S3bp binding pocklet of renin which is essential to its activity |
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Name an ACE inhibitor?
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Captopril, Benazepril, Ramipril
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Name an Angiotensin receptor antagonist?
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Valsartan, Losartan, Candesartan
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Name an aldosterone antagonest?
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Spiranolactone
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What does spironolactone do?
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Aldosterone Antagonist/Potassium sparing diuretic
Causes sodium and water loss |