Exam 3 Flashcards
(198 cards)
Intracellular Fluid
maintaining cell size
70% of total body fluid
about 40% of adult body weight is from ICF
Extracellular
30% of total body fluid and ~20% of body
weight
Intravascular fluid
Type of ECF
plasma of the blood
blood volume, impacts HR/BP
Interstitial Fluid
Type of ECF
surrounds cells
Trans Cellular
Cerebrospinal, Pleural,
Peritoneal, Synovial, Digestive secretions,
Sweat
OSMOLARITY
Concentration of particles in a solution
Isotonic
When the osmolarity is equivalent to plasma
Hypertonic
When the osmolarity is greater than plasma. Hypertonic fluids pull water from the cells and into the intravascular spaces.
Hypotonic
When the osmolarity is less than plasma. Hypotonic fluids move from the intravascular space to the ICF
Normal Saline
Isotonic Solution. Treat hypovolemia, hyponatremia, hypercalcemia, metabolic alkalosis.
Lactated Ringers (LR)
Isotonic Solution. Contains multiple electrolytes. Lacks magnesium. Treats hypovolemia, burns, and GI losses
5% Dextrose in Lactated Ringers (D5LR)
Hypertonic Solution. Replaces electrolytes, provides calories, shifts fluids from cells to vascular space expanding vascular volume
Half strength normal saline (0.45%NaCl)
Hypotonic Solution. Often used as a maintenance fluid. Provides Na Cl and free water
Fluid Intake methods
ingested water, ingested food, metabolic oxidation
Fluid Output methods
kidneys, skin, lungs, gastrointestinal
Kidneys
Filter 180 L of plasma/day while excreting ~1.5 L/day. Manage ECF volume and osmolality. Regulates electrolyte levels by retaining or eliminating.
Heart & Vascular
Circulate fluid, adequate perfusion pressure in kidneys for filtration. Stretch receptors respond to changes in volume and stimulate fluid retention when hypovolemia is present
Heart & Vascular
Circulate fluid, adequate perfusion pressure in kidneys for filtration. Stretch receptors respond to changes in volume and stimulate fluid retention when hypovolemia is present
Lungs
Water vapor excreted/lost per day: 300mL/day
Nervous System
Osmoreceptors (type of neuron) sense changes in ECF concentration and stimulate the pituitary gland to release or inhibit release of ADH. Thirst center in the hypothalamus is activated by cellular dehydration
Gastrointestinal Track
Absorbs water and nutrients
Adrenal Glands
- Aldosterone secretion causes sodium (and
water) retention and potassium loss - Excess cortisol secretion can cause the same
effect as aldosterone
Pituitary Gland
Manages antidiuretic hormone (ADH)
* ADH allows the body to retain water
* ADH in increased when osmotic pressure of
ECF is greater than that of the cells, when
blood volume is decreased
* ADH is suppressed when osmotic pressure
of the ECF is less than that of the cells, or
when blood volume is increased
Thyroid Gland
- Thyroxine secretion least to increased blood
flow, including to the kidneys , whey increases
filtration rate and urinary output