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Flashcards in Body Fluid Compartments Deck (10):

1. Describe the distribution of water and electrolytes within the compartments of the body. (give specific numbers regarding distribution between ICF and ICF, interstitial v. plasma volume)

0.6 of body weight is water
(TBW= total body water)
⅔ of TBW goes to ICF (0.4 x wt.)
⅓ of TBW goes to ECF (0.2 x wt.)

¾ of ECF goes to interstitial fluid (0.15 x wt.)
¼ of ECF goes to plasma (0.05 x wt.)

(wt. is lean body weight)


2. Identify the factors that affect the distribution of fluid among body compartments. (compare the osmolarity of compartments

compartments are separated by semipermeable membranes and water moves freely between compartments so that the effective osmolarity is the same

if you add a solution that is not isotonic to either compartment, you will effect both compartments

Note: proteins and Mg do not exert osmotic force


3. Assess the volume in each of the body compartments. Describe the characteristics of ICF: solutes and what can cause change in volume.

major solutes are K+, phosphates and proteins

changes in sodium concentration change the ICF volume


4. Explain the mechanisms that lead to an imbalance in distribution of fluid or in the amount of fluid in a compartment.

ingestion of water or salts can cause fluid shift between compartments also dehydration, solute or fluid loss

to understand what the balance will be after a disturbance, calculate the original osmoles and volume of ECF and ICF, calculate the new volume and osmoles given the disturbance understanding that osmolarity= osmoles/volume


Contrast osmolarity and osmolality.

osmolarity: osmoles of solute per liter of solution

osmolality: number of osmoles per kg of solvent


Compare the body water content of muscular v. fat patients.

more water in muscle than fat, fat excludes water (note: men typically have a higher muscle content)


3. Assess the volume in each of the body compartments. Describe the solutes and effects of solute change in the ECF.

major solutes include Na, Cl- and bicarbonate
ECF includes both intravascular (plasma) and extravascular (interstitial) volume

changes in sodium content (not concentration) effect ECF


3. Assess the volume in each of the body compartments. Describe the symptoms and signs of changes in ECF.

thirst- angiotensin II
lightheadedness- low volume
palpitations- low volume

signs of low volume:
orthostasis (change in BP more than 20mmHg between standing and laying down)
decreased BP
urine output decrease
dry mouth
dry axilla
low JVP (significant for intravascular volume)
skin turgor/ edema (significant for extravascular and interstitial vol.)


What would happen to cells with isotonic, hypertonic or hypotonic solutions added to the intravascular compartment?

isotonic- not moment of water between compartments, ECF volume increases

hypotonic- movement of water into ICF from ECF; will raise ECF volume, and decrease serum osmolality, increase ICF volume

hypertonic (higher tonicity in comparison to the ECF)- movement of water from ICF to ECF; will raise ECF volume and increase serum osmolality and decrease ICF volume


ECF osmolarity and tonicity are _____ (how are they related), where as ICF osmolarity and tonicity are ________

ECF osmolarity and tonicity are independent

ICF osmolarity and tonicity are intimately tide together