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61 Cards in this Set
- Front
- Back
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clearance of any substance = ?
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urinary excretion/plasma concentration
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what does the clearance of PAH equal?
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effective renal plasma flow (unless the secreting mechanism is saturated)
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what kind of diuretics are contraindicated in renal failure?
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potassium sparing - exacerbates elevated serum potassium & hyperkalemia can lead to arrhythmia
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tubular fluid with lowest osmolarity is found where?
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macula densa
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how is interstitial fluid volume related to inulin space?
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inulin space approximates ECF volume, so interstitial fluid volume = inulin space - plasma volume
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what percent of total body weight is total body water?
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60%
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what proportion of total body water is ECF and ICF?
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1/3 ECF
2/3 ICF |
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what percent of ECF is plasma volume? interstitial volume?
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1/4 plasma volume
3/4 interstitial volume |
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how is plasma volume measured?
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radiolabeled albumin
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how is extracellular volume measured?
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inulin
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formula for clearance?
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C=UV/P
urine concentration x urine flow rate / plasma concentration |
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what forms the size barrier of the glomerulus?
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fenestrated capillary endothelium
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what formes the negative charge barrier of the glomerulus?
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fused basement membrane with heparan sulfate
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what is lost in nephrotic syndrome?
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charge barrier - resulting in albuminuria, hypoproteinemia, generalized edema, and hyperlipidemia
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what substance is used to calculate GFR?
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inulin
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creatinine clearance is an approximate measure of what?
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GFR
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what does renal blood flow equal?
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renal plasma flow/1-Hct
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effective renal plasma flow underestimates true renal plasma flow by how much?
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about 10%
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filtration fraction = ?
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GFR/RPF
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what arteriole does AT II act on?
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preferentially constricts efferent arteriole - decreases RPF, increases GFR, so FF increases
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what dilates the afferent arteriole? what effect does this have?
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prostaglandins - increases RPF, GFR so FF remains constant
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afferent arteriole constriction has what effect?
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decreases RPF & GFR - FF remains constant
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efferent arteriole constriction has what effect?
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decreases RPF, increases GFR, so FF increases
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increased plasma protein concentration has what effect on GFR?
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decreases GFR, (RPF stays same so FF decreases)
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decreased plasma protein concentration has what effect on GFR?
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increases GFR (RPF stays same, so FF increases)
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constriction of ureter has what effect on GFR?
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decreases it (also decreases FF)
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free water clearance = ?
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urine flow rate - clearance(osm)
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at what plasma glucose level does glucosuria begin? at what level does the transport mechanism become saturated?
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200; 350
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the osmolarity of the medulla can reach what level?
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1200 mOsm
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on what type of cells does aldosterone act?
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principal cells of collecting ducts - activates Na+/K+ pump; intercalated cells - stimulates H+ secretion
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portion of the nephron that reabsorbs all of the glucose & AAs, and most of the bicarbonate, sodium, and water; secretes ammonia, which acts as a buffer for H+
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early proximal convoluted tubule
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portion of the nephron that passively reabsorbs water via medullary hypertonicity
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thin descending limb
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portion of the nephron that contains the NKCC and indirectly induces the absorption of Mg2+ and Ca2+; impermeable to water
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thick ascending limb
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location of the nephron in which calcium reabsorption is under the control of PTH?
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early distal convoluted tubule
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actions of the early distal convoluted tubule?
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actively reabsorbs Na+, Cl-; reabsorbs calcium under PTH control
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portion of the nephron that reabsorbs sodium in exchange for secreting potassium or H+? what regulates this?
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collecting tubules; aldosterone
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reabsorption of water in this portion of the nephron is under control of ADH (vasopressin)
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collecting tubules
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actions of angiotensin II?
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potent vasoconstriction
release of aldosterone from adrenal cortex release of ADH from posterior pituitary stimulates hypothamus - increases thirst overall serves to increease intravascular volume and BP |
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what may be released from atria as a check on the RAA system, e.g. in CHF?
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ANP
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what cells secrete renin?
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juxtaglomerular cells - in response to decreased renal BP, decreased Na+ delivery to distal tubule, and increased sympathetic tone
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how can NSAIDs cause acute renal failure in high vasoconstrictive states?
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by inhibiting the renal production of prostaglandins, which keep the afferent arterioles vasodilated to maintain GFR
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where does ADH bind? what is the result?
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binds to receptors on principal cells, causing an increase in the number of water channels/aquaporins and increased H2O reabsorption
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what is ANF secreted in response to? what does it do?
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secreted in response to increased atrial pressure, causes increased GFR and increased Na+ excretion
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what effect does aldosterone have?
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secreted in response to decreased blood volume (via AT II) and increased plasma K+ - causes increased Na+ reabsorption and increased K+ and H+ secretion
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angiotensin II causes increased absorption of what?
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Na+ and HCO3-
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primary disturbance in metabolic acidosis?
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decreased HCO3- (causes hyperventilation/ decreased PCO2)
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primary disturbance in metablic alkalosis?
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increased HCO3- (causes hypoventilation/ increased PCO2)
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primary disturbance in respiratory acidosis?
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increased PCO2 (causes increased renal HCO3- absorption)
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primary disturbance in respiratory alkalosis?
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decreased PCO2 (causes decreased renal HCO3- absorption)
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acidosis with PCO2 >40?
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respiratory acidosis
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acidosis with PCO2 <40?
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metabolic acidosis with compensation
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alkalosis with PCO2 <40?
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respiratory alkalosis
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alkalosis with PCO2 >40?
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metabolic alkalosis with compensation
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causes of respiratory acidosis?
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hypoventilation - airway obstruction, acute/chronic lung disease, opiods, narcotics, sedatives, weakening of respiratory muscles
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causes of anion gap metabolic acidosis?
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MUD PILES
Methanol Uremia Diabetic ketoacidosis Paraldehyde or Phenformin Iron tablets or INH Lactic acidosis Ethylene glycol Salicylates |
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causes of non-anion gap metabolic acidosis?
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diarrhea, glue sniffing, renal tubular acidosis, hyperchloremia
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how do you calculate ion gap?
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Na+ - (Cl- + HCO3-)
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causes of respiratory alkalosis?
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hperventilation, aspirin ingestion (early)
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causes of metabolic alkalosis?
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vomiting, diuretic use, antacid use, hyperaldosteronism
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Winter's formula?
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PCO2 = 1.5(HCO3-) + 8 +/-2
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type of metabolic disturbance commonly seen in cardiopulmonary arrest?
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mixed acidosis
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