Lab. 1 & 2 Serum Electrolytes PDF

1 Lab. 1 & 2 Clinical chemistry 3red Stage Serum electrolytes Serum electrolytes  A cation is an ion with a positive charge. An anion is an ion with a negative charge.  An element or compound that, when melted or dissolved in water or another solvent, dissociates into ions and is...

1 Lab. 1 & 2 Clinical chemistry 3red Stage Serum electrolytes Serum electrolytes  A cation is an ion with a positive charge. An anion is an ion with a negative charge.  An element or compound that, when melted or dissolved in water or another solvent, dissociates into ions and is able to conduct an electric current.  Electrolytes differ in their concentrations in blood plasma, interstitial fluid, and cell fluid and affect the movement of substances between those compartments.  Proper quantities of principal electrolytes and balance among them are critical to normal metabolism and function (eg, nerve impulse transmission, muscular contraction, water balance). Intercellular fluid is present inside the cells, whereas extracellular fluid is present outside the cells. Extracellular fluid is further divided into plasma and interstitial fluid. Plasma is found within the blood vessels, whereas interstitial fluid is present outside the blood vessels  Sodium is the principal extracellular cation and potassium the principal intracellular cation.  2  Typically, the concentration of cations, eg, Na+1, K+1, Ca+2 and Mg+2, is higher in the plasma than in the interstitial fluid, whereas the anions, eg, Cl-1, HPO-4, tend to be higher in the interstitial fluid than the plasma. Serum potassium Overview Sodium-potassium pump (Na+/K+ ATPase)  The cytosol of animal cells contains a concentration of potassium ions (K+) as much as 20 times higher than that in the extracellular fluid. Conversely, the extracellular fluid contains a concentration of sodium ions (Na+) as much as 10 times greater than that within the cell. These concentration gradients are established by the active transport of both ions. Active transport involves the movement of molecules from lower concentration to higher concentration with the use of energy. Passive transport involves the movement of molecules from higher concentration to lower concentration and no amount of energy is required.  The transporter, Na+/K+ ATPase uses the energy from the hydrolysis of ATP to actively transport 3 Na+ ions out of the cell for each 2 K+ ions pumped into the cell. This accomplishes several vital functions:  3  It helps establish a net charge across the plasma membrane with the interior of the cell being negatively charged with respect to the exterior.  This resting potential prepares nerve and muscle cells for the propagation of action potentials leading to nerve impulses and muscle contraction. Why it is done?  Monitoring acute or chronic kidney failure, that can be associated with abnormal potassium levels.  May be ordered at regular intervals to monitor drugs that can cause kidneys to lose potassium, particularly diuretics, resulting in hypokalemia.  Monitor the success of therapy to correct an abnormal high or low blood potassium level.  Monitor certain cancer therapies that may cause cell lysis syndrome, a condition that occurs when cancer cells are rapidly destroyed. Cell lysis syndrome causes abnormally high blood levels of certain electrolytes, including potassium. Normal 3.5–5.2 meq/L Haemolysis of samples cause falsely eleviated K level (Pseudohyperkalemia).  4 Serum sodium Overview  Sodium is the chief cation in fluid residing outside cells in the mammalian body (the so-called extracellular compartment), with relatively little sodium residing inside cells. Functions  Sodium ions are necessary for, transmission of nerve impulses, heart activity, and certain metabolic functions.  The accumulation of sodium ions outside of the cell draws water out of the cell and thus enables it to maintain osmotic balance (otherwise it would swell and burst from the inward diffusion of water). Why it is done?  Evaluate the water balance and electrolyte balance of the body.  Monitor diseases of the kidneys or adrenal glands.  Monitor treatment of certain problems, such as high blood pressure. Normal: 135-145 meq/L 5