Ch 8/9: Altered Fluid & Electrolyte / Acid-Base Balance (Pt 2)

body water (60%)

inside cells (40%) and outside cells (20%)

third-space fluid

found in spina, pleural, and peritoneal; not available for normal fluid exchange

kidenys processes

filtration, reabsoprtion, secretion

Filtration

occurs in glomerulus; blood pressure forces water & small solutes from blood into the Bowman’s capsule

reabsorption

occurs in renal tubules; essential substances are reclaimed and returned to capillaries

secretion

moves waste products and excess substances from peritubular capillaries into the renal tubule

hydrostatic pressure

push fluid out of the capillary

oncotic (colloid osmotic) pressure

push fluid back to capillary

fluid regulation

mechanisms that regulate total body water

promote fluid intake

decrease in blood volume, increase extracellular osmolality, stretch receptors in arteries, angiotensin II

promote fluid excretion

diuretics (decrease sodium reabsorption)

tonicity

osmotic pressure of an extracellular solution; allows water to move into or out of cells

isotonic

balanced; replenish water

hypertonic solution

excrete flulid

hypotonic solutoin

secrete fluid

hypovolemia

decreased vascular volume; caused by hemorrhage, dehydration, water intoxication, third spacing

hypervolemia

excessive extracellular fluid; caused by heart failure, liver cirrhosis, kidney failure