Deck 35: Control of Body Fluid Osmolality and Volume

Question 1

A patient has polyuria and polydipsia,and the urine osmolality is 100 mOsm/kg H₂O.The polyuria and polydipsia are not corrected by intravenous injection of ADH,and the exogenous ADH does not alter urine osmolality.What is the probable disorder in this patient?

A)SIADH
B)Osmotic diuresis
C)Central diabetes insipidus
D)Nephrogenic diabetes insipidus
E)Nephrolithiasis (renal stone)

Answer 1

D

Question 2

An individual is stricken with an illness characterized by nausea,vomiting,and diarrhea.Over a 2-day period,this individual experiences a 3-kg loss in weight without a change in the plasma [Na⁺].What can be concluded about body fluid volumes and composition in this individual?

A)The volume of intracellular fluid (ICF)is increased.
B)The volume of extracellular fluid (ECF)is reduced.
C)The total body osmolar volume is increased.
D)The plasma osmolality is reduced.

Answer 2

B

Question 3

A patient has polyuria and polydipsia,and the urine osmolality is 100 mOsm/kg H₂O.After an intravenous injection of ADH,urine volume decreases and urine osmolality increases.What is the probable disorder in this patient?

A)Syndrome of inappropriate ADH secretion (SIADH)
B)Osmotic diuresis
C)Central diabetes insipidus
D)Nephrogenic diabetes insipidus
E)Nephrolithiasis (renal stone)

Answer 3

C

Question 4

A 56-year-old woman has congestive heart failure with generalized edema.Which of the following plays an important role in the formation of edema in this woman?

A)Increased interstitial hydrostatic pressure
B)Decreased interstitial oncotic pressure
C)Increased plasma oncotic pressure
D)Decreased renal excretion of Na⁺
E)Decreased venous pressure

Question 5

Which of the following maneuvers would be expected to stimulate antidiuretic hormone (ADH)secretion?

A)Infusion of 1 L hypertonic NaCl
B)Infusion of 1 L of an isoosmotic urea solution
C)Expansion of the extracellular volume fraction (ECV)
D)Infusion of 1 L of 5% dextrose in water (D₅W)
E)An acute increase in blood pressure

Question 6

A 78-year-old woman with congestive heart failure develops pitting edema in her legs.In comparison with a healthy (i.e.,euvolemic)individual,what set of parameters would be expected in this woman?

Question 7

Vasopressin has which of the following actions?

A)It increases the water permeability of the thick ascending limb of Henle's loop.
B)It increases the urea permeability in the cortical portion of the collecting duct.
C)It increases the water permeability in the collecting duct.
D)It decreases the GFR.
E)It increases the water permeability in the proximal tubule.

Question 8

The kidneys maintain a constant plasma osmolality by regulating the excretion of which of the following?

A)Glucose
B)Na⁺
C)Creatinine
D)H₂O
E)K⁺

Question 9

Which of the following situations would be expected to cause an increase in ADH secretion by the posterior pituitary gland?

A)A 5% decrease in arterial blood pressure
B)A 5% increase in arterial blood pressure
C)A 1% decrease in plasma osmolality
D)A 1% increase in plasma osmolality

Question 10

Hyponatremia can sometimes be seen in individuals whose ECF volume is decreased by more than 10%.Which of the following factors contributes to the development of hyponatremia in this situation?

A)Decreased levels of ADH
B)Elevated levels of natriuretic peptides
C)Increased excretion of Na⁺ by the kidneys
D)Reduced excretion of solute-free water by the kidneys
E)Development of positive Na⁺ balance

Question 11

Which of the following will occur with a decrease in the ECF volume?

A)Increase in glomerular filtration rate (GFR)
B)Increase in angiotensin II levels
C)Increase in natriuretic peptide levels
D)Increase in free H₂O clearance
E)Increase in fractional excretion of Na⁺

Question 12

A 45-year-old woman has a blood pressure of 140/90 mm Hg.Her doctor recommends a low-salt diet.When she has reached a new steady state on her new diet,what would her serum [Na⁺] and ECF volume become in comparison with their values on her previous diet?