fluid, electrolyte, acid-base balance Flashcards
what are the body fluid compartments
intracellular and extracellular
what is the intracellular compartment
critical for maintaining cell size, 70% of total body fluid, about 40% of adult body weight is from ICF
what is the extracellular compartment
30% of total body fluid, about 20% of body weight; contains intravascular fluid, interstitial fluid, trans cellular
what is intravascular fluid
in the extracellular; plasma of the blood-> blood volume, impacts HR/BP
what is interstitial fluid
in extracellular; surrounds cells
what is trans cellular
in extracellular; cerebrospinal, pleural, peritoneal, synovial, digestive secretions, sweat
what is osmolarity
the concentration of particles in a solution
what is isotonic
when the osmolarity is equivalent to plasma
where does isotonic fluid remain
in the intravascular space
what is hypertonic
when the osmolarity is greater than plasma
what do hypertonic fluids do
pull water from the cells and into intravascular spaces; cell shrinks
what is hypotonic
when the osmolarity is less than plasma
what do hypotonic fluids do
move from the intravascular space to the ICF; cell swells
isotonic solutions treat?
hypovolemia, hypercalcemia, metabolic alkalosis
hypertonic solutions replace?
electrolytes, provides calories, shifts fluid form cells to vascular space expanding vascular volume
hypotonic solutions are used as?
a maintenance fluid, provides Na, Cl, and free water
how is fluid balance achieved
with oral intake of fluid matching the output of the kidneys; match I & O
how do kidneys manage fluid and electrolyte balance
filter 180 L of plasma/day while excreting 1.5 L/day; regulate electrolyte levels by retaining or eliminating
how does the heart and vascular manage fluid and electrolyte balance
circulate fluid, adequate perfusion pressure in kidneys for filtration, stretch receptors respond to change in volume and stimulate fluid retention when hypovolemia is present
how do the lungs manage fluid and electrolyte balance
water vapor excreted/lost per day, about 300mL/day
how does the nervous system manage fluid and electrolyte balance
osmoreceptors sense changes in ECF concentration and stimulate the pituitary gland to release or inhibit release of ADH
how does the GI track manage fluid and electrolyte balance
absorbs water and nutrients
what glands have hormonal control of fluid and electrolyte balance
adrenal glands, thyroid gland, pituitary gland, parathyroid gland
aldosterone secretion causes
sodium (and water) retention and potassium loss
pituitary gland manages
antidiuretic hormone (ADH)