GMS 6401 EXAM PRACTICE QUESTIONS
AND 100% VERIFIED CORRECT ANSWERS!!
T/F: sodium is the major cation in the ECF
true
T/F: sodium content of ECF determines ECF volume
true
Which forms of sodium output are not regulated? Which are? Why?
feces and sweat are not regulated as they account for less than 10% of sodium output; urine is
regulated
natriuresis
increase in sodium excretion
antinatriuresis
decrease in sodium excretion
When does the sodium balance shift from equilibrium to positive?
during maturational growth and pregnancy
What diseases can affect sodium balance?
adrenal deficiency (negative balance, Na+ wasting)
CKD, nephrotic syndrome, liver cirrhosis, heart failure (positive balance, Na+ retention)
How is sodium excretion (UNaV) determined?
UNaV = amount filtered - amount reabsorbed
What are the salt values within the body?
what we need: ~1/4 tsp
what we eat: 3+ tsp
, what we excrete: 3+ tsp
what we filter: 1.5x
T/F: Sodium reabsorption requires energy expenditure so it is metabolically very costly
true
T/F: filtration is the first step in determining UNaV
true
increase in GFR leads to increase in filtered sodium leading to an increase in UNaV
What is the limiting mechanism to filtration?
glomerulotubular balance
What are the baseline filtration conditions?
GFR = 120 mL/min
UNa = 84 meq/L
PNa = 140 meq/L
V = 1 mL/min
filtered sodium = 16.8 meq/min
UNaV = 0.084 meq/min
How to calculate diltered sodium?
filtered Na = GFR x PNa
What causes glomerulotubular balance?
1. luminal control: tubular epithelium senses an increase in delivery of sodium and increases
reabsorption in response (flow dependence)
2. starling pressures: links GFR and proximal reabsorption
T/F: An increase in GFR does not cause a large, acute increase in UNaV although over time
it becomes very significant
true
AND 100% VERIFIED CORRECT ANSWERS!!
T/F: sodium is the major cation in the ECF
true
T/F: sodium content of ECF determines ECF volume
true
Which forms of sodium output are not regulated? Which are? Why?
feces and sweat are not regulated as they account for less than 10% of sodium output; urine is
regulated
natriuresis
increase in sodium excretion
antinatriuresis
decrease in sodium excretion
When does the sodium balance shift from equilibrium to positive?
during maturational growth and pregnancy
What diseases can affect sodium balance?
adrenal deficiency (negative balance, Na+ wasting)
CKD, nephrotic syndrome, liver cirrhosis, heart failure (positive balance, Na+ retention)
How is sodium excretion (UNaV) determined?
UNaV = amount filtered - amount reabsorbed
What are the salt values within the body?
what we need: ~1/4 tsp
what we eat: 3+ tsp
, what we excrete: 3+ tsp
what we filter: 1.5x
T/F: Sodium reabsorption requires energy expenditure so it is metabolically very costly
true
T/F: filtration is the first step in determining UNaV
true
increase in GFR leads to increase in filtered sodium leading to an increase in UNaV
What is the limiting mechanism to filtration?
glomerulotubular balance
What are the baseline filtration conditions?
GFR = 120 mL/min
UNa = 84 meq/L
PNa = 140 meq/L
V = 1 mL/min
filtered sodium = 16.8 meq/min
UNaV = 0.084 meq/min
How to calculate diltered sodium?
filtered Na = GFR x PNa
What causes glomerulotubular balance?
1. luminal control: tubular epithelium senses an increase in delivery of sodium and increases
reabsorption in response (flow dependence)
2. starling pressures: links GFR and proximal reabsorption
T/F: An increase in GFR does not cause a large, acute increase in UNaV although over time
it becomes very significant
true
