lab 3 Flashcards
what is total body water?
the sum of all the water contained in the body compartments, including intracellular and extracellular
what is an index of short-term total body water change?
body weight
how can you monitor changes in the different compartments?
via dilution markers
what % of body weight is the total body water?
60%
what % of the body weight is the intracellular fluid
40%
what % of body weight is the extracellular fluid?
20%
what % of body weight is the interstitial fluid?
15%
what % of body weight is the plasma?
5%
what % of body weight is the transcellular fluid?
variable (fluid found in body cavities)
in new borns, are the body water spaces higher or lower than in adults? which space is the same as adults?
the body water is higher; the intracellular volume space is the same
what is intracellular fluid?
it is the fluid in all cells
what is the interstitial fluid
it is the fluid that immediately surrounds the cells but is also outside the blood vessels
what is the plasma volume?
it is the fluid volume within the vasculature
what is the transcellular fluid?
it is the fluid found in the body cavities (such as intraocular, CSF synovial, urine, bile, intestinal secretions)
how do you find the volume of plasma?
use a known amount of solute; the concentration of the solute - the amount of solute/concentration. measure the marker over time and extrapolate back to zero to find the instantaneous concentration
loss of dye during the time it is distributing can be problematic
what can be used to measure plasma volume?
evan’s blue.
what can be used to measure extracellular water volume?
thiocyanate (KSCN)
how do you find the extracellular water volume?
determine the volume by the equation
concentration of marker=amount/volume then substract the volume of plasma
how do you calculate blood volume?
multiply the plasma volume by (100%-PCV)
what do you use to measure total body water?
deuterated D2O or 40AAP
or dessication until dry
how do you calculate the intracellular volume?
measure total body water via deuterated water and substract extracellular volume
