Sodium Functions• Transmission and conduction of nerve impulses• Responsible for osmolality of vascular fluids• Regulation of body fluid levels• Sodium shifts into cells and potassium shifts outof the cells (sodium pump)• Assists with regulation of acid-base balance bycombining with Cl or HCO3 to regulate thebalance
Chloride Functions• Found in ECF• Changes the serum osmolality• Goes with Na in retention of water• Assists with regulation of acid-base balance• Cl combines with hydrogen to form hydrochloricacid in the stomach
Potassium function Potassium cation are important in neuron function. Potassium influencing osmotic balance between cellsand the interstitial fluid, with their distribution by theso-called Na+/K+-ATPase pump. K+: essential for normal membrane excitability fornerve impulse Contraction of muscle Promotes enzyme action Assist in the maintenance of acid-base
Bicarbonate function Bicarbonate is alkaline and a vital component of thepH buffering system of the human body (maintainingacid-bace homeostasis).
Normal rangesPotassium 3.5-5.1mmol/LChloride 101-112mmol/LSodium 136-145mmol/LBicarbonate 22-32mmol/L
Rules of Electrolyte Balance1. Most common problems with electrolyte balance arecaused by imbalance between gains and losses ofsodium ions2. Problems with potassium balance are less common,but more dangerous than sodium imbalance
• HyponatremiaExcessive sodium loss or H2O gain• CAUSES– Prolonged diuretic therapy– Insufficient Na intake– vomiting– Administration of hypotonic fluids– Compulsive water drinking– alcoholism
Hypernatremia• Occurs with excess loss of H2O or excessiveretention of Na• Can lead to death if not treated• Causes– Vomiting/diarrhea– Inadequate ADH– Some drugs– Hypertonic fluids/tube feedings– Major burns
Hyperkalemia• Results form impaired renal function• Metabolic acidosis• Acts as myocardial depressant; decreased heartrate, cardiac output• Muscle weakness• GI hyperactivity
Method of detection Photoelectric flame photometer In principle, it is a controlled flame test with theintensity of the flame quantified by photoelectrically.The sample is introduced to the flame at a constantrate. Filters select which colours the photometerdetects and exclude the influence of other ions.
Ion selective electrode The sample is mixed with ISE providing constantpH.As the buffered sample is moved through the ionselective electrode , changes in the electrical potentialtake place .The electrical potential changes aremeasured against the potential of a refrence electrode.