Ionic compounds that dissociate into ions when placed in water and are capable of conducting electricity.
An ion having a positive electric charge due to the loss of one or more electron.
An ion having a negative charge due to the gain of one or more electrons.
Molecules that do not dissociate into ions when placed in water. (Poor conductors of electric current)
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)
The pressure required to stop osmosis through a semi-permable membrane between solutions of different solute concentrations.
The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per kilogram of solute.
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
Equal osmolality both inside and outside the cell.
No net water (solvent) movement.
Cell size remain the size.
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)
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)`
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.
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.)
Increased plasma osmolality, ADH secretion and thrist sensation are activated.
Composes about one third of the body fluid (37%)
Intravascular - Plasma (blood or lymph)
Intertitial - Fluid that surrounds the cells
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)
Steroid hormone responsible for Sodium reabsorption and Potassium excertion.
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.
Elevated levels of sodium in the blood
Hyperaldosteronism, Excessive saline I.V., Short term vomiting and diarrhea, Polyuria, and rapid breathing
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.
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.
Elevated levels of potassium in the blood. Hemolyzed specimen, Dehyration, burns, and Hypoaldosteronism.
Decreased levels pf potassium in the blood. Chronic starvation, alcoholism, vomiting, diarrhea, Hyperaldosteronism and some diuretics.
The major anion of extracellular fluid, counterbalances the sodium cation (Na+). Absorbed in the small intestine.
Osmotic pressure which controls water distribution, Mainteinances of electrical neutrality in body, and combines with hydrogen in gastric mucosal glands to form HCl.
Elevated levels of chloride in the blood.
Dehydration, prolonged diarrhea, and excessive saline IV.
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.
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.
85% of HCO3- ions are reabsorbed by the proximal tubules.
15% of HCO3- ions are replaced by the distal tubules.
Decreased pCO2 (partial pressure CO2) due to compensation by hyperventilation.
Regulated by parathyroid hormone (PTH)
Exists in three forms -Ionized free form, Protein-bound, and complexed.
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.
Hyperparathyroidism, Excessice vitamin D, and Parathyriod tumors.
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.
Major intercellular anion
Phosphate homeostasis regulated by parathyriod hormone (PTH)
Acid and base balence, mineral phase of bone, ATP production, and Structural component of cell membranes and nucleic acids.
Hypoparathyroidism, any major surgery or trauma involving massive bone destruction, and chemotherapy.
Hyperparathyroidism and Alcoholism
Exists in three forms Ionized (free), Protein-bound, and complexed.
PTH causes increased reabsorption by the kidneys, PTH enhances intestinal absorption.
Cofactor for over 300 enzymes, Carbohydrate metabolism, and Muscle contraction.
Antacids, renal failure, and Hyperparathyroidism
Malabsorption, kidney reabsorption problems, and hypoparathyroidism
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.