GMS 6401 EXAM REVIEW QUESTIONS
WITH ACCURATE SOLUTIONS 2026
▶ how does total body water change when person becomes more obese.
Answer: total body water will decrease and % of fat will increase
little water in fat
▶ what divides the intracellular and extracellular fluid. Answer: cell wall
(plasma membrane)
▶ what controls the fluid movement between the interstitial and plasma.
Answer: Starling Pressures
▶ what is the definition of osmolality. Answer: the number of free
(dissociated) particles in solution
units are osm or mosm/kg of H2O
▶ what determines the osmolality in body fluids. Answer: the number of
particles
NOT size of the particles
▶ what determines the osmolality in the ECF. Answer: charged
electrolytes (ions) which associate to produce a molecule and dissociate in
solution
▶ is the osmolality the same of different between the ICF and ECF.
Answer: the same
about 290-300 mosm/kg H2O
▶ why is osmotic equilibrium possible. Answer: the cell membrane is freely
permeable to water
▶ in which direction does water move. Answer: from low to high
concentration
▶ what is an isotonic solution. Answer: no osmotic gradient
, no water movement
healthy cell
▶ what is a hypertonic solution. Answer: more particles outside cell than
inside cell
water leaves cell
cell shrinks
▶ what is a hypotonic solution. Answer: more particles inside cell than
outside
water moves in
cell swells and bursts (hemolysis)
▶ what happens to the cell when you add pure water to the solution.
Answer: both ICFV and ECFV expand
osmolality falls
water will flow from blood to plasma across barrier into cell
▶ what happens to the cell when you add isotonic NaCl (IV infusion).
Answer: no change in volume in ICFV
ECFV expands bc NaCl can't cross membrane
no water movement across barrier
no change in osmolality
infusion is isoosmotic
▶ what happens to the cell when you add pure NaCl (eat a very salty
meal). Answer: ICFV shrinks
ECFV expands
osmolality increases everywhere
water leaves cell
▶ what is a hypertonic contraction. Answer: happens during heavy
sweating
dehydration
loss of excess water without loss of NaCl
both ECF and ICF volumes decrease
increase in osmolality due to excess loss of H2O
▶ what is an isotonic contraction. Answer: equivalent loss of salt and H2O
diarrhea, vomiting
WITH ACCURATE SOLUTIONS 2026
▶ how does total body water change when person becomes more obese.
Answer: total body water will decrease and % of fat will increase
little water in fat
▶ what divides the intracellular and extracellular fluid. Answer: cell wall
(plasma membrane)
▶ what controls the fluid movement between the interstitial and plasma.
Answer: Starling Pressures
▶ what is the definition of osmolality. Answer: the number of free
(dissociated) particles in solution
units are osm or mosm/kg of H2O
▶ what determines the osmolality in body fluids. Answer: the number of
particles
NOT size of the particles
▶ what determines the osmolality in the ECF. Answer: charged
electrolytes (ions) which associate to produce a molecule and dissociate in
solution
▶ is the osmolality the same of different between the ICF and ECF.
Answer: the same
about 290-300 mosm/kg H2O
▶ why is osmotic equilibrium possible. Answer: the cell membrane is freely
permeable to water
▶ in which direction does water move. Answer: from low to high
concentration
▶ what is an isotonic solution. Answer: no osmotic gradient
, no water movement
healthy cell
▶ what is a hypertonic solution. Answer: more particles outside cell than
inside cell
water leaves cell
cell shrinks
▶ what is a hypotonic solution. Answer: more particles inside cell than
outside
water moves in
cell swells and bursts (hemolysis)
▶ what happens to the cell when you add pure water to the solution.
Answer: both ICFV and ECFV expand
osmolality falls
water will flow from blood to plasma across barrier into cell
▶ what happens to the cell when you add isotonic NaCl (IV infusion).
Answer: no change in volume in ICFV
ECFV expands bc NaCl can't cross membrane
no water movement across barrier
no change in osmolality
infusion is isoosmotic
▶ what happens to the cell when you add pure NaCl (eat a very salty
meal). Answer: ICFV shrinks
ECFV expands
osmolality increases everywhere
water leaves cell
▶ what is a hypertonic contraction. Answer: happens during heavy
sweating
dehydration
loss of excess water without loss of NaCl
both ECF and ICF volumes decrease
increase in osmolality due to excess loss of H2O
▶ what is an isotonic contraction. Answer: equivalent loss of salt and H2O
diarrhea, vomiting
