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72 Cards in this Set
- Front
- Back
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Flow equation?
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Q=change in P/Vascular Resistance
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4 things involved in physiological control of RBF and GFR?
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Autoregulation
Tubuloglomerular Feedback Sympathetic Nerves Nitric Oxide |
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Where do sympathetic nerves exhibit control on RBF and GFR?
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Afferent Arteriole (constriction/dilation)
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Equation for GFR?
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Kf X Net Ultrafiltration Pressure
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What ='s Net Ultrafiltration Pressure?
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Glomerular Hydrostatic Pressure -
Bowman's Capsule Pressure - Glomerular Colloid Osmotic Pressure |
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Test to estimate GFR?
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creatinine/inulin clearance
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What happens to the rate of creatinine excretion as the plasma concentration of it increases?
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Excretion increases in proportion. This is due to the fact that creatinine is neither reabsorbed or excreted in the kidney.
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What happens to creatinine clearance as plasma [creatinine] inc
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Nothing. Clearance ratio is the same
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Clearance of Creatinine =?
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(Urine Creatinine X Volume)/Plasma Inulin
=GFR |
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Significance of PAH Clearance?
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PAH is totally secreted (i.e. not filtered, not reabsorbed) so it can be used to estimate Renal Plasma Flow
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Where in the nephron is water permeability ALWAYS low?
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Thick Asc Limb of LOH
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Receptors for ADH?
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V1 (vascular)
V2 (renal tubular) |
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Where is ADH synthesized?
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Hypothalamus
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Secretion of ADH controlled by?
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Osmoreceptors (triggered by hypertonic)
Volume Receptors (triggered by dec pressure) |
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What is the most potent stimulator for ADH secretion?
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Inc Plasma Osmolarity
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What is Desmopressin and what is it used for?
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Its a ADH analog
Used in D.I., Hemostatic Disease, Nocturnal Enuresis |
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Rx for SIADH?
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Water Restriction (#1)
Hypertonic Saline (3%) Loop Diuretics Demeclocycline (secondary) |
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What is Demeclocycline?
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Tetracycline derivative
Antagonizes ADH actions, but not a receptor antagonist |
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What is the point of Uricosuric Drugs?
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Promote Excretion of Uric Acid
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Types of Uricosuric Drugs?
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Probenecid
Sulfinpyrazone (anturane) |
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MOA of Uricosuric Drugs?
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Dec uric acid reabsorption in PCT (for gout)
Dec PCT secretion of penicillin (reduce excretion) |
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SE's of Uricosuric Drugs?
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Renal Stones
Stomach Irritation |
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Serum Na in SIADH?
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LOW
due to dilutional effect of ADH-induced water retention ADH DOES NOT AFFECT NA REABSORPTION |
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MOA for Eplerenone?
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Aldosterone Antagonist
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Where is the majority of salt and water reabsorbed in the kidney?
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PCT
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Normal GFR?
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125mL/min/1.73m(squared)
180L/day |
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Total Plasma Volume?
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3L
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How many times is the total plasma volume filtered per day?
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60 times (180L/day)
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Avg daily urine output?
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2L
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Determinants of Filtration?
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Renal Plasma Flow
Net Pressure Gradient Capillary Surface Area Capillary Permeability |
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3 processes that determine urinary excretion of a substance?
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Glomerular Filtration
Reabsorption of Substance by tubules Secretion of substance by tubules |
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Equation for calculating Urinary Excretion Rate?
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GFR - Reabsorption Rate + Secretion Rate
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Clearance = ?
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([Urine X] x Volume)/ [Plasma X]
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Normal Range for Cr Clearance?
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97-137mL/min for men
88-128 for women |
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Why is Cr clearance lower for women?
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they have a lower muscle mass
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Requirements for an Ideal Marker to measure to determine GFR?
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Freely Filtered across glomerulus
Not Reabsorbed Not Secreted Not synthesized in tubules Not degraded in Tubules |
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Best markers for GFR?
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Inulin
Creatinine Urea |
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Which one is the gold standard?
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Inulin, but it's $$$ and cumbersome, so we usually just stick with Cr
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Why isn't Cr perfect?
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10% is secreted so it overestimates GFR
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What happens to Cr levels in renal failure?
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Cr Level Increases
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What happens to Cr Clearance in Renal Failure?
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It DECREASES
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Clinical Conditions that causes Cr:GFR errors?
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Ketoacidosis
Drugs Inc Protein Intake Muscle Wasting |
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Other estimates for GFR?
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Cockcroft-Gault Formula
MDRD Formula |
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what's up with The Cockcroft Gault Formula
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Takes in to account age
(140-age) x LBW / PCr[mg/dL] x 72 multiply by .85 for women |
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Problems with Cockcroft?
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Overestimates GFR in:
vegetarians low protein diet malnourished edematous pts Advanced kidney disease |
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What's up with MDRD formula?
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Not good for various ethnicities
Not good for very old or very young Not good for diabetics takes in to account Cr, BUN, age, gender, race, albumin |
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Urea levels in Renal Failure?
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INCREASE
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What happens to Urea in the nephron?
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freely filtered
reabsorbed in PCT and distally Affected by volume status (volume depleted-->inc [urea]) |
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What is BUN?
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Blood Urea Nitrogen
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BUN increases w/?
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Reduced effective circulating blood volume
Catabolic states High Protein Diets GI bleeding Glucocorticoids Tetracycline |
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BUN decreases w/?
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Liver Disease
Malnutrition Sickle Cell SIADH |
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Most tests can use a random blood sample, which one needs a 24 hour urine and blood sample?
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Cr Cl
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equation for comparing RBF and RPF?
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RBF = RPF/1-hematocrit
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~ RBF?
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1.1L/min
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RPF =?
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(1-.45) x 1.1 = 605mL/min
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most widely used marker for RPF?
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PAH
Para-aminohippurate |
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What is Filtration Fraction?
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GFR/RPF
fraction of plasma filtered through glomerular membrane |
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what should filtration fraction =?
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~20%
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Equations for Reabsorption Rate and Secretion Rate?
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Filtered Load - Excretion Rate
Excretion Rate - Filtered Load |
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Urine Flow Rate?
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1mL/min
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normal urine and plasma Na concentrations
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U-Na=70mEq/L
P-Na = 140mEq/L |
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What's up with Fractional Excretion of Na?
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Assessment of Tubular Integrity
Should be low (.5%) |
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Normal Size of Kidneys in an Adult?
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9-12cm
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Normal cortex and renal sinus on Ultrasound?
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Cortex: hypoechoic
Sinus: echogenic |
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Ultrasound finding w/ renal disease?
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Inc Cortical Echogenicity
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Appearance of Kidneys w/ chronic kidney disease?
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Shrunken
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Normal size + Echogenic Kidneys = ?
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Acute GN
Acute Tubular Necrosis |
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Normal size + normal echogenicity = what kind of diseases (possibly)
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Prerenal acute kidney injury
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Enlarged kidneys =?
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Malignant infiltration
Amyloidosis HIV nephropathy (type 1 diabetes??) |
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Pelvicalyceal Dilation =?
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obstruction
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When is a renal angiogram good?
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For Atherosclerotic Renal Artery Stenosis
Fibrodysplastic Renal Artery Stenosis Vasculitis Renal Masses |
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Contraindication for a Renal Biopsy?
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Multiple Cysts
Solitary Kidney Infection (acute pyelonephritis) Renal Neoplasm Uncontrolled HTN or bleeding diathesis Uncooperative Patient |
