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81 URINALYSIS/BODY FLUIDS...

81 URINALYSIS/BODY FLUIDS by Michele Zitzmann* Kidney Nephron Distal Tubule lomeru 1,1 Cortex /' H+ I Medulla \ Proximal ! Tubule Glucose Salts - - - -'I-"! Amino Acids Ureter u::: ollecting J ") Loop of Henle Diagrams adopted with permission from Modem Urine Chemis/JY Manua/;Siemens Healthcare Diagnostics Inc~ 1996 Renal Physiology 2. on-selective filter of plasma NEPHRON substances of less than 70,000 MW 1. Major functional unit of the kidney 3. Water, glucose, electrolytes, amino acids , urea, uric acid, creatinine, and 2. Approximately I million per kidney ammonia comprise the glomerular filtrate 3. Composed of glomerulus and r enal tubules 4. Filters 120 ml/min, or one-fifth of renal GLOMERULUS plasma 1. Coil of capillary vessels TUBULES FUNCTION Reabsorbs water, Sodium Chloride, Bicarbonate, Potassium, Calcium, Amino Acids, Proximal Tubule Phosphates, Protein, and Glucose Glucose - Threshold Substance -Reabsorb at 160-180 mg/di or less Secretes - Sulfates, glucuronides, Hydrogen ions and drugs loop of Henle Reabsorbs water Descending No solutes reabsorbed Loop of Henle Reabsorbs Solutes (Sodium, Chloride, Calcium, and Magnesium Ascendin2 No water reabsorbed Distal & Collecting Reabsorbs Sodium Tubules Secretes Potassium, Ammonia and Hydrogen ions Potassium ions exchanged for sodium ions *od ginal contribution hy LilJhy Spence 82 URINE VOLUME VOLUME DISEASE AND CAUSES Normal Average of 1200-1500 ml/day Polyuria >2500 ml/day Diabetes insipidus, Diabetes mellitus, diuretics Caffeine, alcohol, excessive water intake Oliguria