Lecture 19 Electrolytes PDF

Electrolytes Electrolytes Electrolytes Minerals that carry an electrical charge Negative ions or anions Positive ions or cations Are found in all body fluids Functions Role in maintenance of water balance & fluid osmotic pressure Role in normal muscular and nervous...

Electrolytes Electrolytes Electrolytes Minerals that carry an electrical charge Negative ions or anions Positive ions or cations Are found in all body fluids Functions Role in maintenance of water balance & fluid osmotic pressure Role in normal muscular and nervous functions maintain and activate several enzyme systems acid-base regulation  Major Electrolytes in Plasma Cations Calcium: Ca++ Magnesium: Mg++ Sodium: Na+ Potassium: K+ Anions Chloride: Cl− Bicarbonate: HCO3− Inorganic phosphorus: PO4 Protein Electrolyte Assays Changes in electrolyte concentration can result from: Increased or decreased intake. Shifts of electrolyte between ECF and ICF. Increased or decreased renal retention. Arterial samples are ideal for analysis of electrolytes and blood gases Analyze immediately Cations Sodium (Na2+) Major cation of plasma and the ECF Important role in water distribution and body fluid osmotic pressure maintenance Sodium heparin tubes—falsely elevated sodium levels Conditions Associated with Altered Sodium Levels Potassium (K+) Major intracellular cation Hyperkalemia- Functions increase in plasma K+ important in normal levels muscular function Due to cellular Respiratory, Cardiac, necrosis/tissue Skeletal damage, urinary nerve impulse transmission obstruction, carbohydrate metabolism hypoadrenocorticism Sampling Considerations Hypokalemia— Plasma preferred —K+ may decreased K+ levels be released during clotting Due to inadequate K+ Avoid hemolysis—releases intake, alkalosis, or K+ fluid loss from vomiting or diarrhea Potassium (K+) as an Intracellular Buffer K+ in the plasma and ECF affects the plasma concentration of H+ and vice versa. K+ and H+ are positively charged ions that move freely between ICF and ECF. ↓ in plasma K+ cause potassium to move from cells to the ECF and H+ to move from the ECF into the cells. ↑ plasma potassium levels result in potassium moving into the cells and hydrogen ions moving into the ECF. Conditions Associated with Altered Potassium Levels  Magnesium (Mg2+) Second most common intracellular cation Found in all body tissues More than 50% in bones Activates enzyme systems Imbalance of Mg/Ca ratio can result in muscular tetany from the release of acetylcholine. Cattle and sheep only animals that show clinical signs related to Mg deficiencies. Hypermagnesemia or hypomagnesemia Anticoagulants other than heparin may decrease results.  Calcium (Ca2+)