Fluids, Electrolytes, and Acid Base

basic vocab terms chapter 13, 14

Anions

Negatively charged electrolytes.

Calcium (Ca2+)

An important body electrolyte ion having two positive charges (divalent cation).

Cations

Positively charged electrolytes.

Dehydration

Body fluid volume deficit caused by fluid intake or retention below what is needed to meet the body’s daily fluid needs.

Diffusion

Movement of particles (solute) across a permeable membrane from an area of higher particle concentration to an area of lower particle concentration (down a concentration gradient).

Electrolytes (ions)

Solute particles that express an overall electrical charge (positive or negative). Also known as ions.

Extracellular fluid (ECF)

The compartment composed of fluids outside of the cells (interstitial fluid and plasma volumes).

Facilitated diffusion

Movement across a cell membrane that requires a membrane-altering system.

Filtration

Movement of fluid through a cell or blood vessel membrane because of hydrostatic pressure (water pressure) differences.

Fluid and electrolyte balance

Regulation of body fluid volume, osmolarity, and composition; the regulation of electrolytes by the processes of filtration, diffusion, osmosis, and selective excretion.

Hydrostatic pressure

Pressure exerted by water molecules against the surfaces (membranes or walls) of a confining space. Also known as water pressure.

Hypercalcemia

Total serum calcium level above 10.5 mg/dL or 2.62 mmol/L.

Hyperkalemia

Serum potassium level higher than 5.0 mEq/L (mmol/L).

Hypermagnesemia

Serum magnesium level above 2.1 mEq/L or 1.05 mmol/L.

Hypernatremia

Serum sodium level over 145 mEq/L (mmol/L).

Hyperosmotic/Hypertonic

Fluid with an osmolarity greater than 300 mOsm/L.

Hypervolemia

Fluid overload.

Hypocalcemia

Total serum calcium (Ca2+) level below 9.0 mg/dL or 2.25 mmol/L.

Hypokalemia

Serum potassium level below 3.5 mEq/L (mmol/L).

Hypomagnesemia

Serum magnesium (Mg2+) level below 1.3 mEq/L or 0.65 mmol/L.

Hyponatremia

Serum sodium (Na+) level below 136 mEq/L (mmol/L).

Hypo-osmotic/Hypotonic

Fluid with an osmolarity less than 270 mOsm/L.

Hypovolemia

Lower than normal circulating blood volume.

Insensible water loss

Body water loss that has no mechanisms for control, including losses through the skin, the lungs, GI tract, salivation, and drainage from fistulas and drains.

Interstitial fluid

The part of extracellular fluid present between cells, also called the third space; it includes blood, lymph, water in the bones and connective tissue, and transcellular fluids.

Intracellular fluid (ICF)

The compartment composed of fluid inside the cells (cellular fluid).

Isosmotic/Isotonic

Fluid that has the solute (particle) concentration (osmolarity) within the normal range for human body fluids (270 to 300 mOsm/L).

Magnesium (Mg2+)

An ion that is stored mostly in bones and cartilage.

Obligatory urine output

Minimum amount of urine output per day needed to excrete toxic waste products (400 to 600 mL).

Osmolality

The number of milliosmoles in a kilogram of solution.

Osmolarity

The number of milliosmoles in a liter of solution.

Osmosis

Movement of water only through a selectively permeable (semipermeable) membrane to achieve an equilibrium of osmolarity.

Potassium (K+)

The major cation of the intracellular fluid (ICF).

Sodium (Na+)

The major cation (positively charged particle) in the extracellular fluid (ECF).

Solute

Particles dissolved in the solvent of body fluids.

Solvent

The water portion of body fluids.

Acid-base balance

The maintenance of arterial blood pH between 7.35 and 7.45 through control of hydrogen ion production and elimination.

Acidosis

Arterial blood pH level below 7.35.

Acids

Substances that release hydrogen ions when dissolved in water (H2O) or body fluids, increasing the amount of free hydrogen ions in that solution.

Alkalosis

Arterial blood pH level above 7.45.

Bases

Substances that bind free hydrogen ions in solution and lower the amount of free hydrogen ions in solution.

Buffers

Substances that when dissolved in fluid can react as either an acid (releasing a hydrogen ion) or a base (binding a hydrogen ion), depending on the pH of that fluid.

Hyperventilation

Rate and depth of breathing increased above normal.

Hypoventilation

Rate and depth of breathing decreased below normal.

Kussmaul respiration

A pattern of breathing associated with acidosis in which breaths are deep and rapid.