Electrolytes

Cards (88)

  • Electrolytes
    Ions capable of carrying an electric charge (+/-)
  • Types of electrolytes
    • Cations
    • Anions
  • Cations
    • Have positive charge
    • Migrate toward the cathode
  • Cations
    • Mg2+
    • Ca2+
    • Zn2+
    • Na+
    • K+
  • Hyponatremia
    <135 mmol/L
  • Hypernatremia
    High sodium concentration
  • Anions
    • Have negative charge
    • Migrate toward the anode
  • Anions
    • Cl-
    • HCO3-
    • PO4-
  • Functions of electrolytes
    • Volume and osmotic regulation
    • Myocardial rhythm and contractility
    • Important cofactors in enzyme activation
    • Regulation of ATP ion pumps
    • Maintenance of acid-base balance
    • Neuromuscular excitability
    • Blood coagulation
    • Production and use of ATP from glucose
  • 40-75% is the average water content of the human body
  • Excess fluid

    Suppresses ADH
  • Lack of fluid

    Stimulates ADH
  • Extracellular Fluid (ECF)

    Fluid outside the cells, represents 1/3 of total body
  • Intravascular ECF (plasma)
    93% water, inside the veins
  • Interstitial fluid
    Water around the cells, 7% of ECF
  • Intracellular Fluid (ICF)
    Water within the cells, represents 2/3 of total body water
  • ADH (Antidiuretic Hormone)

    Also known as AVP (Arginine Vasopressin Hormone)
  • Sodium (Natrium)
    Major extracellular cation (90% of all extracellular cations), outside of the cell, principal osmotic particle outside the cell
  • Reference values for sodium: 135-145 mmol/L
  • Hypernatremia
    Sodium concentration >145 mmol/L, report immediately
  • Hyponatremia
    Sodium concentration <120 mmol/L, report immediately
  • Causes of hypernatremia
    • Excess water loss
    • Decreased water intake
  • Causes of hyponatremia
    • Excess water loss
    • Increased water retention
    • Water imbalance
  • Methods of sodium determination
    • Flame Emission Photometer
    • Ion Selective Electrode
    • Atomic Absorption Spectrophotometry
    • Colorimetry
  • Potassium (Kalium)
    Major intracellular cation (only 2% circulates in plasma), single most important analyte in terms of an abnormality being immediately life threatening
  • Reference value for potassium: 3.5-5.2 mmol/L
  • Factors affecting potassium levels
    • Hemolysis
    • Muscular activity
    • Prolonged contact of serum and red cells
    • Prolonged tourniquet application
    • High bicarbonate levels
  • Causes of hyperkalemia
    • Decreased renal excretion
    • Extracellular shift
    • Increased intake
    • Artifactual
  • Causes of hypokalemia
    • Gastrointestinal loss
    • Intracellular shift
    • Renal loss
  • Magnesium
    Second most abundant intracellular cation, 4th most abundant cation, essential cofactor of more than 300 enzymes, involved in cardiovascular and neuromuscular functions
  • Reference value for magnesium: 1.2-2.1 mEq/L
  • Forms of magnesium
    • Free or ionized (55%)
    • Complexed with ions (15%)
    • Bound to proteins (30%)
  • Causes of hypermagnesemia
    • Decreased excretion
    • Increased intake
  • Causes of hypomagnesemia
    • Decreased intake
    • Decreased absorption
    • Increased excretion
  • Chloride
    Major extracellular anion (counterpart of Na in extracellular fluid), promotes maintenance of osmolality, blood volume and electric neutrality, only anion to serve as an enzyme activator
  • Reference value for chloride: 98-107 mmol/L
  • Factors affecting chloride levels
    • Hemolysis
    • Reduced intake
    • Increased excretion
  • Bicarbonate
    2nd most abundant anion in the ECF, accounts for 90% of total CO2 at physiologic pH, buffers excess hydrogen by combining with acid, major component in buffering system of blood
  • Reference value for bicarbonate: 21-28 mEq/L (venous blood plasma or serum)
  • Calcium
    Present almost exclusively in the plasma, involved in blood coagulation, enzyme activity, excitability of skeletal and cardiac muscle, maintenance of BP