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Electrolytes Unit 2 MLT

Unit 2 Medical Education and Training Campus Program: Medical Laboratory Technician Course: CHEM 101 Chemistry 1
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Electrolytes
Ionic compounds that dissociate into ions when placed in water and are capable of conducting electricity.
Cation
An ion having a positive electric charge due to the loss of one or more electron.
Anion
An ion having a negative charge due to the gain of one or more electrons.
Non-electrolytes
Molecules that do not dissociate into ions when placed in water. (Poor conductors of electric current)
Osmosis
The passage of solvent from a solution of lesser solute concentration to one of greater solute concentration when the solutions are separated by a semi-permable membrane. (Does not require any energy)
Osmotic Pressure
The pressure required to stop osmosis through a semi-permable membrane between solutions of different solute concentrations.
Osmolality
The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per kilogram of solute.
Osmolarity
The concentration of osmotically active particles in solution reported in milliosmoles per liter; not routinely used.
Three Types of Tonics
Isotonic, Hypertonic, and Hypotonic Solutions
Isotonic Solution
Equal osmolality both inside and outside the cell.
No net water (solvent) movement.
Cell size remain the size.
Hypertonic Solution
Higher osmolality outside than inside the cell.
Water moves out of the cell in an attempt to equalize the concentration of solution.
Cell shrinks (crenates)
Hypotonic Solution
Lower osmolality outside the cell than inside the cell.
Water moves into cell in an attempt to equalize the concentrations of solution.
Cell swells, with the potential to rupture (hemolysis)`
Osmolality Controls
Fluid intake (Sensation of thirst), Increases water content in the extracellular fluid.
Secretion of ADH (vasopressin), Released by the Posterior Pituitary Gland, water re-absorption.
Osmotic Activity
Sodium, Chloride and Bicarbonate account for approximately 90-92% of the activity in the plasma.
Excess Intake of Water
Lower plasma osmolality, Suppressed ADH and the sensation of thrist. (In the absence of ADH, water is not reabsorbed.)
Water Deficit
Increased plasma osmolality, ADH secretion and thrist sensation are activated.
Extracellular Compartment
Composes about one third of the body fluid (37%)
Intravascular - Plasma (blood or lymph)
Intertitial - Fluid that surrounds the cells
Intracellular Compartment
Composes about two third of the body fluid (63%)
Consists of the fluid in all body cells.
Sodium (Natrium- NA+)
Major cation in the extracellular fluid.
Represents 90% of all plasma cations.
Daily intake (adult's <2.4g/day)
Aldosterone
Steroid hormone responsible for Sodium reabsorption and Potassium excertion.
Sodium Functions
Maintains osmotic pressure of blood, helps regulate blood pressure, contributes to acid/base balence, promotes normal nerve impluse transmission and muscle contraction, and helps reabsorb water.
Hypernatremia
Elevated levels of sodium in the blood
Hyperaldosteronism, Excessive saline I.V., Short term vomiting and diarrhea, Polyuria, and rapid breathing
Hyponatremia
Prolonged vomiting, Persistent diarrhea, Hypoaldosteronism, and diuretics.
Potassium (Kalium - K+)
Major cation of the intracellular fluid
Daily allowance is 3.5g/day.80-90% of ingested potassium is excreted by kidneys.
Potassium Functions
Helps maintain proper muscle contractions, esp. the heart, maintains the osmotic pressure of cells helps maintain the electrical neutrality of the cells, and promotes nerve impluse transmission and muscle contraction.
Hyperkalemia
Elevated levels of potassium in the blood. Hemolyzed specimen, Dehyration, burns, and Hypoaldosteronism.
Hypokalemia
Decreased levels pf potassium in the blood. Chronic starvation, alcoholism, vomiting, diarrhea, Hyperaldosteronism and some diuretics.
Chloride (Cl-)
The major anion of extracellular fluid, counterbalances the sodium cation (Na+). Absorbed in the small intestine.
Chloride Functions
Osmotic pressure which controls water distribution, Mainteinances of electrical neutrality in body, and combines with hydrogen in gastric mucosal glands to form HCl.
Hyperchloremia
Elevated levels of chloride in the blood.
Dehydration, prolonged diarrhea, and excessive saline IV.
Hypochloremia
Decreased levels of chloride in the blood.
Any acidosis caused by increased production of organic acid (called metabolic acidosis), and severe vomiting.
Total Carbon Dioxide (TCO2)
Measurment of TCO2 is done to evaluate HCO3 levels.
Bicarbonate and dissolved CO2 are directly involved in the body's acid-base balence.
Bicarbonate HCO3
The second most abundent extracellular anion.
Accounts for 90% of the total CO2 at physiological pH.
Diffuse out of the cell in exchange for chloride and maintains ionic charge neutrality within the cell.
Bicarbonate Metabolism
85% of HCO3- ions are reabsorbed by the proximal tubules.
15% of HCO3- ions are replaced by the distal tubules.
Metabolic Acidosis
Decreased pCO2 (partial pressure CO2) due to compensation by hyperventilation.
Calcium
Regulated by parathyroid hormone (PTH)
Exists in three forms -Ionized free form, Protein-bound, and complexed.
Calcium Functions
Calcium is the major structural componentand represents 99%of the bone and teeth in the body, Critical to coagulation, Muscle contrations, and nerve impulse transmision.
Hypercalcemia
Hyperparathyroidism, Excessice vitamin D, and Parathyriod tumors.
hypocalcemia
Hypoparathyroidism, Vitamin D deficiency, and malabsorption.
Measuring Ionized Calcium Directly
Newborn, Transfusion with large volumes of blood or plasma containing calcium-binding anticoagulants, and Hemodialysis.
Phosphate
Major intercellular anion
Phosphate homeostasis regulated by parathyriod hormone (PTH)
Phosphate Functions
Acid and base balence, mineral phase of bone, ATP production, and Structural component of cell membranes and nucleic acids.
Hyperphosphatemia
Hypoparathyroidism, any major surgery or trauma involving massive bone destruction, and chemotherapy.
Hypophosphatemia
Hyperparathyroidism and Alcoholism
Magnesium
Exists in three forms Ionized (free), Protein-bound, and complexed.
PTH causes increased reabsorption by the kidneys, PTH enhances intestinal absorption.
Magnesium Functions
Cofactor for over 300 enzymes, Carbohydrate metabolism, and Muscle contraction.
Hypermagnesemia
Antacids, renal failure, and Hyperparathyroidism
Hypomagnesemia
Malabsorption, kidney reabsorption problems, and hypoparathyroidism
Anion Gap
The concentration of undetermined anions present in the blood, Calculated as the difference between the measured total cations and the measured total anions.
Increased Anion Gap
Decreased unmeasured cations from hypokalemia, hypocalcemia, and hypomagnesium.
Decreased Anion Gap
Hypercalemia, hyperkalemia, hypermagnesium, and paraproteins
Methods of Electrolyte Measurement
Ion selective electrode (ISE), Gas electrode, enzymatic, Spectrophotometic, and Reduction.