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30 Cards in this Set
- Front
- Back
Range of possible urine osmolarity
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50 - 1400 mOsm/L
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Describe solute excretion with and without ADH
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Solute excretion is minimally increased (~0.1 mOsm/min) with ADH
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Osmolarity of the filtrate in the proximal tubule
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300 mOsm/L
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Osmolarity of the filtrate in the most medullary of the loop of Henle
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up to 1200-1400 mOsmol/L
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How many mOsmoles of solute must a 70kg person excrete every day?
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600 mOsmoles
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If a 70kg person can maximally excrete 1200 mOsmol/L of concentrated urine, what is the obligatory amount of urine that has to be made every day
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0.5 L
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How much of the maximum concentration of urine (1200mOsmoles/L) is NaCl?
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half
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What is the NaCl concentration of sea water?
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1200mOsmol/L
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So how much must you pee to get rid of the NaCl provided by 1 L of sea water?
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2 L
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Where in the nephron is urea permeant?
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"proximal
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What makes urea more permeant in the inner medullary collecting duct?
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"urea transporters (eg, Ut-AI)
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what kind of diet will allow a person to better concentrate their urine?
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high protein diet
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in the setting of dehydration and low sodium intake, can the kidneys form highly concentrated urine?
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yes, using urea and creatinine to increase osmolarity
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what is free water clearance?
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flow of urine - osmolar clearance
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What does it mean when free water clearance is negative?
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water is being conserved and returned to the body.
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Failure to produce ADH is called what?
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central diabetes insipidus
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treatment for central diabetes insipidus?
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desmopressin
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What drugs may cause neprhogenic diabetes insipidus?
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lithium
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What is the treatment for neprogenic diabetes insipidus?
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correct the unerlying disorder
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Normal plasma osmolarity is 300mOsmol/L. If you had to calculate it from Na concentration, what's the formula?
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Plasma osmolarity = 2.1 * Na conc
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What do you add to the Na+ concentration if your pt is diabetic?
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glucose and urea concentration
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What's at the upper part of the AV3V region that affects ADH?
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subfornical region
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What's at the lower part of the AV3V region that affects ADH?
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organum vasculosum of the lamina terminalis
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What's inbetween the subfornical region and the organum vasculosum of the lamina terminalis?
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median preoptic nucleus
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what is weird about the subfornical nucleus and organum vasculosum of the lamina terminalis considering it is brain tissue (or is it?)?
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they have vascularity that has no blood brain barrier
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b) osmotic increase
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b) osmotic increase
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d) alcohol
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a) nausea
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What is the threshold for drinking?
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2mEq/L more than normal Na+ in the ECF
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The most important regulator of Na+ plasma osmolarity?
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ADH-thirst mechanism
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Even though these hormones are released in part by a low concentration of Na+, they are pretty useless at increasing the CONCENTRATION of Na+
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Angiotensin II and Aldosterone
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