Chapter 21: Water, pH, and Electrolyte Balance

intracellular fluìd

fluid inside cells

extracellular fluid

fluid outside cells that includes interstitial fluid, blood plasma, lymph, transcellular fluid

transcellular fluid

fluid separated by epithelial layers (CSF, synovial and serous fluid, aqueous and vitreous humors)

rises

what does osmotic pressure of extracellular fluid due in response to water loss

osmoreceptor-ADH mechanism

controls the concentration of urine produced in kidney

salt cravings

what does severe electrolyte deficiency cause?

positive

types of ions needed for nerve impulses, muscle fiber concentration, and maintenance of cell membrane permeability

acids

electrolytes that ionize in water and release hydrogen ions

bases

substances that combine with hydrogen ions

H+

ion released by strong acids

OH-

ion released by strong bases

chemical buffer system

first line of defense in maintaining internal environment

bicarbonate buffer system

bicarbonate ion converts strong acid to weak acid and carbonic acid converts strong base to weak base

phosphate buffer system

monohydrogen phosphate ion converts a strong acid to a weak acid and dihydrogen phosphate converts strong base to weak base

protein buffer system

NH₃ group releases a hydrogen ion in the presence of excess base and COO^- group accepts a H⁺ ion in the presence of excess acid

respiratory excretion of CO2

if body produces too much CO2, H+ concentration rises and pH lowers, so body increases rate and depth of respiration to eliminate more CO2

renal excretion of H+ ions

nephrons help regulate the H+ ion concentration of the body fluids by excreting H+ ions in the urine

acidosis

results from accumulation of acids or loss of bases

alkalosis

results from accumulation of bases or loss of acids