Fluid/Electrolytes Flashcards
Extracellular fluid (ECF)
fluid outside the cell
1/3 of body’s H20
more prone to loss
3 types
3 types of extracellular fluid:
Interstitial: fluid around/between cells
Intravascular: (plasma) fluid in blood vessels
Transcellular- CSF, synovial fluid, etc
Intracellular fluid (ICF)
Fluid inside the cell
Most 2/3 of body’s H20 is in the ICF
Infant fluid compartments:
60% of H20 is found in the ECF
40% of H20 is found in ICF
Adults or infants are more prone to fluid loss?
Infants!
Body tries to maintain homeostasis of fluids and electrolytes by regulating:
volumes
solute charge and osmotic load
What is the minimum output her hour necessary to maintain renal function?
30mL/hr
Loss of 10% body fluid= ______-weight loss and is _____
8% weight loss and is SERIOUS
Loss of 20% body fluid = _____ weight loss and is _____
15% weight loss and is FATAL
Electrolytes:
charged particiles
cations- positively charged ions
Na+, K+, Ca++, H+
Anions: negatively charged ions
Cl-, HCO3-, PO43-
Non electrolytes:
uncharged particles- proteins, urea, glucose, O2, CO2
Functions of body fluid (6)
medium for transport
cellular metabolism
solvent for electrolytes and other constituents
body temperature
digestion and elimination
lubricant
Hypothalamus:
thirst receptors
osmoreceptors monitor serum osmolarity.
If it rises, thirst mechanism is triggered
Sodium is found in the
extracellular compartment
Potassium is found in the
intracellular compartment
Magnesium is found more in the
intracellular compartment
Chloride is found in the
extracellular compartment
Solute homeostasis is maintained by
ion transport
water movement
kidney function
these functions act to keep body fluids:
electrically neutral
osmotically stable
Diffusion
movement of particles DOWN a concentration gradient
Facilitated diffusion
addition of specific carrier molecules to aid/accelerate diffusion (glucose transport into cell facilitated by insulin)
Osmosis
diffusion of water across a selectively permeable membrane
Active transport
movement of particles UP a concentration gradient; REQUIRES ENERGY
Osmolarity (tonicity)
concentration of particles in a solution
the greater the concentration (osmolarity) of a solution, the greater the pulling force (osmotic pressure)
A solution that has a HIGH osmolarity is a _____ solution
HYPERTONIC solution
A solution that has a LOW osmolarity is a _____ solution
HYPOTONIC solution
A solution that has EQUAL osmolarity is a ________ solution
ISOTONIC (normal saline)
Hypertonic fluids have a _____ concentration of particles (high osmolality) than ICF
higher!
Higher osmotic pressure shifts fluid from the cells into the
ECF
Cells placed in a hypertonic solution will
SHRINK!!!!!!
Hypertonic solution is used to
temporarily treat hypovolemia
expand vascular volume
fosters normal BP and good urinary output (often used post op)
Hypotonic fluids have less concentration of particles than
ICF
The low osmotic pressure shifts fluid from
ECF into cells
Cells placed in a hypotonic solution will
SWELL!
Hypotonic solution is used to
dilute plasma particularly in hypernatremia
treats cellular dehydration
do not use for patients with increased ICP risk or third spacing risk- edema!
Isotonic fluids have the same concentration of particles (osmolality) as
ICF
Osmotic pressure is therefore the _____ inside and outside the ____
SAME
cell
Cells do not ___ or ____ in an isotonic solution. They _____
DO NOT SWELL OR SHRINK
THEY STAY THE SAME!
Isotonic solution expands…
both intracellular and extracellular volume
used commonly for excessive vomiting and diarrhea
0.9% normal saline
D5W
Ringer’s Lactate