Chapter 5
The osmolality of a solution containing 1.0 mole of urea is equal to that of a solution containing...
0.5 mole of NaCl
The ultrafiltrate in the urinary space of the glomerulus has a specific gravity of?
1.010 and the same osmolality as the blood plasma
What percentage of the total cardiac output is received by the kidneys?
25%
The daily volume of urine excreted normally ranges from?
500 to 1800 mL/day
What situation results in an erroneous creatinine clearance measurement?
A 24 hour urine collection maintained at room temperature throughout the collection
What renal function is assessed using specific gravity and osmolality measurements?
Concentrating ability
What is an endogenous substance used to measure glomerular filtration rate?
Creatinine
The concentration of what substances provides the best means of distinguishing urine from other body fluids?
Creatinine and urea
What solute affects the specific gravity more than it affects osmolality if pure water is added?
Glucose
Occasionally the specific gravity of a urine specimen exceeds that physiologically possible(1.040). What substances found in the urine could account for such a high value?
Mannitol
What group of individuals would be expected to have the greatest 24 hour excretion of creatinine?
Men
What is the definition of the osmolality of a solution?
The number of solute particles per kilogram of solvent
What solutes are present in the largest molar amounts in urine?
Urea, chloride, and sodium
Oliguria
a significant decrease in the volume of urine excreted (<400 mL/day)
The oral ammonium chloride test evaluates the ability of the tubules to secrete...
ammonia and hydrogen
All of the following conditions may produce nocturia except? -anuria -pregnancy -chronic renal disease -fluid intake at night
anuria
A fluid deprivation test is used to...
assess renal concentrating ability
A free water clearance value of -1.2 would be expected from a patient experiencing ...
dehydration
Nocturia
excessive or increased frequency of urination at night
When the body is dehydrated, the kidneys...
excrete solutes in as small a volume of urine as possible
The volume of plasma cleared per minute in excess of that required for solute elimination is called the ...
free-water clearance
A 24 hour urine collection is preferred for determination of creatinine clearance because of diurnal variation in the...
glomerular filtration rate
Creatinine is a good substance to use for a renal clearance test because it...
has a constant plasma concentration
Polydipsia
intense and excessive thirst
For measurement of renal plasma flow, p-aminohippurate is an ideal substance to use because it ...
is secreted completely in its first pass through the kidneys
Creatinine clearance results are "normalized" using an individual's body surface area to account for variation in the individual's
muscle mass
Renal excretion is not involved in the elimination of ...
normal by products of fat metabolism
Osmolality is a measure of solute ...
number
The excretion of less than 400 mL of urine per day is called?
oliguria
Serum osmolality remains relatively constant, whereas the urine osmolality ranges from ...
one to three times that of serum
A fluid deprivation test involves the measurement of serum and urine ...
osmolality
The maximum osmolality that urine can achieve is determined by the ...
osmolality of the medullary interstitium
Renal clearance is defined as the volume of...
plasma cleared of a substance in a time interval
Another name for excessive thirst is ...
polydipsia
The excretion of large volumes of urine (>3 L/day) is called...
polyuria
Specific gravity measurements are not affected by ...
solute charge
Anuria
the absence of cessation of urine excretion
Polyuria
the excretion of large volumes of urine (>3 L/day)
The glomerular filtration rate is controlled by..
the renal blood flow
Measuring the quantity of hydrogen ion excreted as titratable acids and ammonium salts in urine provides a measure of...
tubular secretory function
