acid base / fluid electrolyte balance

positive balance

intake of substance (like water or electrolytes) exceeds its loss

negative balance

loss of a substance exceeds intake

intracellular fluid (ICF)

fluid found inside cells; makes up about 2/3 of total body fluid

extracellular fluid (ECF)

fluid outside cells; includes interstitial fluid and plasma

interstitial fluid

fluid between cells in tissues; part of the ECF

plasma

the fluid portion of blood; part of the ECF

total body fluid

the sum of ICF and ECF in the body

hyperosmotic

a solution with a higher solute concentration that another

hypoosmotic

a solution with a lower solute concentration than another

isosmotic

two solutions with equal solute concentrations

hypertonic

a solution that causes cells to shrink (water leaves the cell)

hypotonic

a solution that causes cells to swell (water enters the cell)

isotonic

a solution with no net water movement into or out of cells

thirst

the body’s signals to increase water intake, triggered by dehydration or high plasma osmolarity

acid

a substance that donates H+ ions; lowers pH

base

a substance that accepts H+; raises pH

pH

a measure of H+ ion concentration; scale of acidity/basicity (0-14)

respiratory acidosis

low blood pH due to hypoventilation and CO2 buildup

respiratory alkalosis

high blood pH due to hyperventilation and CO2 loss

metabolic acidosis

low blood pH from excess acid or loss of bicarbonate

metabolic alkalosis

high blood pH from loss of acid or excess bicarbonate

buffer

a system that resists changes in pH by neutralizing added acids or bases pr

protein buffer system

uses amino acid side chains to buffer pH; works mainly inside cells and plasma

hemoglobin buffer system

buffers pH in red blood cells by binding or releasing H+

bicarbonate buffer system

major buffer in blood; HCO3 neutralized acids, and carbonic acid neutralizes bases p

phosphate buffer system

buffers pH in ICF and kidneys using H2PO4 and HPO4

no compensation

the body has not yet responded to an acid-base imbalance

partial compensation

the body has begun to respond to the imbalance, but pH is still abnormal

full compensation

the body has corrected the pH back to normal, but underlying cause may still exits