BRS

Question 1

60-40-20 rule

Answer 1

Total body water = 60
ICF = 40
ECF = 20
ECF is made up of plasma (1/4) and interstitial fluid (3/4)

Question 2

mannitol is a marker for which water compartment

Answer 2

ECF because it is a large molecule that cannot cross cell membranes and is therefore exluded from ICF

Question 3

Evans blue is a marker for which water comparrtment

Answer 3

plasma volume becuase it is a dye that binds to serum albumin and is therefore confined to the plasma compartment

Question 4

total body water markers

Answer 4

Tritiated H2O
D2O
Antipyrene

Question 5

ECF markers

Answer 5

sulfate
inulin
mannitol

Question 6

plasma markers

Answer 6

RISA (radioiodinated serum albumin)

Evans blue

Question 7

Interstitial fluid markers

Answer 7

ECF- plasma volume (indirect)

Question 8

ICF marker

Answer 8

TBW - ECF (indirect)

Question 9

isosmotic volume expansion
ECF volume _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/Hematocrit?

BP?

Answer 9

e.g. isotnoic NaCl infusion
ECF volume increases
no change in osmolarity
no water shift

Plasma protein/hematocrit decrease because addition of fluid to ECF dilutes protein/RBCs but RBCs do not swell due to no osmolarity chagne

BP increases

Question 10

Loss of iostonic fluid
ECF _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/hematocrit?

BP?

Answer 10

e.g. diarrhea
ECF decreases but no change in osmolarity and therefore no water shift

plasma protein/hematocrit increase because loss of ECF concentrates protein and RBCs but RBCs do not shrink/swell

BP decreases

Question 11

Hyperosmotic volume expansion
ECF _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/hematocrit?

BP?

Answer 11

e.g. excessive NaCl intake - addition of NaCl
ECF osmolarity increases because osmoles have been added to ECF
Water shifts from ICF –> ECF and as a result, ICF osmolarity increases until it = ECF osmolarity

–> water shifts out of cells, ECF volume increases and ICF volume decreases

Plasma protein/hematocrit decrease because of increase in ECF volume

Question 12

hyperosmotic volume contraction
ECF _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/hematocrit?

BP?

Answer 12

e.g. sweating in a desert - loss of water
Osmolarity of ECF increases because sweat is hyposmotic (more water than salt is lost)
ECF volume decreases because loss of volume in sweat. water shifts out of ICF and ICF osmolarity increases and volume decreases

plasma protein concentration increases
hematocrit remains unchanged because water shifts out of RBCs, decreasing their volume and offsetting concentrating effect of decreased ECF volume

Question 13

Hyposmotic volume expansion
ECF _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/hematocrit?

BP?

Answer 13

e.g. Syndrome of inappropriate ADH (SIADH) - gain of water
osmolarity of ECF decreases because excess water
ECF volume increases
Water shifts into cells, ICF osmolarity decreases and volume increases
Plasma protein concentration decreases
Hematocrit remains unchanged because RBCs take on water

Question 14

Hyposmotic volume contraction
ECF _______
change in osmolarity of ECF? ICF?
water shift?

Plasma protein/hematocrit?

BP?

Answer 14

e.g. adrenocortical insufficiency - loss of NaCl
osmolarity of ECF decreases because no aldosterone (decreased NaCl reabsorption and kidneys excrete more NaCl than water)
ECF volume decreases, water shifts into cells and ICF osmolarity decreases while volume increases
plasma protein concentration increases
hematocrit increases because decreased ECF volum,e and RBCs swell
Blood pressure decreases