Renal Function

    Cards (32)

    • Nephron - basic structural & functional unit of the kidney
      • 1 to 1.5 million nephrons PER kidney
      • consists of glomerulus and renal tubules
    • Total Renal Blood Flow: 1200 mL/min
    • Total Renal Plasma Flow: 600-700 mL/min
    • Glomerulus - "working portion" of the kidney
    • Glomerulus - resembles a "SIEVE"
    • Glomerulus - non-selective filter of plasma substances with MW of <70k Da
    • MW = <70k Da
    • Renal Threshold for Glucose = 160-180mg/dL
    • Glomerular Filtrate: Specific Gravity - 1.010
    • PCT is the major site (65%) of reabsorption
    • DAM - collects water, so does the Descending Loop of Henle
    • ASIN-ding loop = REABSORBS ASIN (salt), but NOT water
    • ACTIVE transport - the movement of a substance across the cell membranes into the bloodstream by electrochemical energy
    • PASSIVE transport - the movement of molecules across a membrane by diffusion because of a physical gradient
    • Glucose, Amino Acids, Salts - PCT
    • ADH (Anti-Diuretic Hormone) or Vasopressin - regulates WATER REABSORPTION in the DCT and CD
    • ADH Deficiency = Diabetes insipidus (DI)
    • ADH Excess = SIADH (Syndrome of Inappropriate ADH Secretion)
    • Aldosterone - regulates SODIUM REABSORPTION in the DCT
    • RAAS (Renin-Angiotensin-Aldosterone System)
      1 - Angiotensinogen
      2 - Angiotensin I
      3 - Angiotensin II
    • PCT (Proximal Convoluted Tubule) - major site for removal of unfiltered substances
    • CLEARANCE Tests - used to evaluate Glomerular Filtration
    • Creatinine = MOST COMMON
    • Inulin - GOLD STANDARD (Reference Method)
    • Inulin = MW: 5200 Da
    • COCKGROFT and GAULT Variables
      • Age
      • Sex
      • Body weight in kg
    • Cockcroft-Gault Formula: Clearance (mL/min) = [(140Age)(Weight in Kg)/72] x Creatinine clearance (mg/dL)
    • MDRD (Modification of Diet in Renal Disease) Variables
      • Ethnicity
      • BUN
      • Serum Albumin
    • Concentration Tests - used to evaluate tubular reabsorption
    • FISHBERG Test - used for the OBSOLETE test
      • patient is deprived of fluid for up to 24 hours
    • p-amino hippuric acid (PAH) test - most commonly used; reference method for Tubular Secretion and Renal Blood Flow
    • phenolsulfonphthalein (PSP) test - obsolete, results are hard to interpret