body fluids lect 3 Flashcards
the extracellular fluid is composed of what two main portions?
1) Plasma
2) Interstitial fluid
Total body water is comprised of what percentage of body weight?
60%
total body water (TBW) is composed of what two primary portions?
intracellular fluid and extracellular fluid
what is the 60-40-20 rule
% distribution: TBW = 60% of body weight; ICF = 40%; ECF = 20%
how does water content correlate with body fat stores? Who has the highest % of water; who has the lowest % of water
water content correlates inversely with body fat stores –thin men = highest %; obese women = lowest %
What is the equation to calculate Total Body Water
TBW = 0.7 LBM + 0.1 AT LBM = lean body mass (kg) and AT = adipose tissue (kg)
if proportion of Lean body mass is not known, how can TBW be calculated? What makes this estimation less accurate?
TBW = 0.6 (weight); not accurate for adults with % of adipose tissue markedly greater than 20%
Interstitial fluid and plasma have essentially the same ionic makeup. What is the difference?
ISF does not have plasma proteins or RBC
what is the major cation in ISF and plasma
NA+
What are the major anions in ISF and plasma
Cl- and HCO3-
what is the major cation of ICF
K+
what are the major anions of ICF
proteins and organic phosphates
what is the osmolarity of ICF, ISF, and plasma at equilibrium?
290 mOsm/L
what is the equation to calculate osmolarity
2 (Na+) + glucose/18 + BUN/2.8
any loss or gain of water and/or electrolytes must initially occur in which compartment?
ECF
* if equilibrium is upset, then ICF changes will also occur
what is hematocrit
fraction of plasma occupied by RBC after centrifugation: height of RBC/Total height
saline infusion signifies what type of process?
isosmotic volume expansion: gain of isotonic solution
In isosmotic volume expansion, what happens to TBW, plasma protein, and hematocrit?
TBW increases; Plasma protein decreases; Hematocrit decreases (diluted due to increase in ECF volume)
in isosmotic volume expansion, is there a change in ECF osmolarity?
No, isotonic volume gain
in isosmotic volume expansion, is there a shift in H20 between ICF and ECF? Does ICF volume change?
No; no change in ICF volume
diarrhea is an example of what process
isosmotic volume contraction: loss of isotonic solution
What happens to TBW, plasma protein, and hematocrit in isosmotic volume contraction
TBW decreases; plasma protein increases; hematocrit increases
drinking pure water or SIADH-syndrome of inappropriate anti-dieretic hormone secretion are examples of what type of process
hyposmotic volume expansion: gain of hypotonic solution
in hyposmotic volume expansion, where does water move?
From ECF to ICF. ECF will increase; osmolarity will decrease because gave body hypotonic solution; ICF will increase (net flow from ECF to ICF) net flow of water from lower osmolarity to higher osmolarity
In hyposmotic volume expansion, what happens to TBW, plasma protein, and hematocrit levels?
TBW increases; Plasma protein decreases; hematocrit decreases slightly
water depravation and sweating are examples of what type of process
hyperosmotic volume contraction: loss of hypotonic solution
In hyperosmotic volume contraction, what happens to TBW, plasma protein, and hematocrit levels
TBW decreases; plasma protein increases; slight increase in hematocrit
what happens to the osmolarity of ECF in hyperosmotic volume contraction? Where does water flow because of this?
osmolarity of ECF increases; water will travel from ICF to ECF
what units is total plasma protein measured in? Therefore, a decrease in ECF will have what impact on plasma protein?
g/dL; increase
high NaCl intake is an example of what type of process
hyperosmotic volume expansion
in hyperosmotic volume expansion, what happens to levels of TBW, plasma protein, and hematocrit?
TBW remains same (no addition of fluid); Plamsa protein decreases; hematocrit decreases (diluted due to increase in ECF volume)
in hyperosmotic volume expansion, what happens to the osmolarity of ECF? What effect does this have on osmosis?
ECF osmolarity increases; water will move from ICF to ECF
loss of sodium from aldosterone insufficiency is an example of what type of process
hyposmotic volume contraction
in hyposmotic volume contraction, what happens to the osmolarity of ECF? What effect does this have on osmosis?
osmolarity of ECF decreases; water moves into ICF
In hyposmotic volume contraction, what happens to the levels of TBW; plasma protein; and hematocrit?
TBW levels stay the same (no loss of fluid); plasma protein increases; hematocrit increases
in isotonic glucose infusion; where does glucose go once in the ECF? What does glucose break down to form in the cells?
Glucose travels into ICF where it is broken down into water and CO2.
in isotonic glucose infusion, what happens to levels of TBW, plasma protein, and hematocrit
TBW increases since glucose breaks down into H20 and CO2; this causes osmolarity of ICF to decrease and water will travel from ICF into ECF; therefore; plasma protein decreases and hematocrit decreases
what does isosmotic; hyperosmotic; and hyposmotic mean in terms of ECF
isosmotic: no change in osmolarity of ECF; hyperosmotic: increase in osmolarity of ECF; hyposmotic: decrease in osmolarity of ECF
what does contraction and expansion (word used in type of fluid shift) mean?
contraction: decrease in ECF volume; expansion: increase in ECF volume
