NSG 170 (Health Illness concepts) Fluid and Electrolyte
Elsevier Quizzes Questions With Complete Solutions
Which cation regulates intracellular osmolarity?
ANS: Potassium
Rationale: A decrease in serum potassium causes a decrease in
the cell wall pressure gradient and results in water moving out of
the cell. Besides intracellular osmolarity regulation, potassium
also regulates metabolic activities, transmission and conduction
of nerve impulses, cardiac conduction, and smooth and skeletal
muscle contraction. Sodium is the most abundant extracellular
cation that regulates serum osmolarity as well as nerve impulse
transmission and acid-base balance. Calcium is an extracellular
cation necessary for bone and teeth formation, blood clotting,
hormone secretion, cardiac conduction, transmission of nerve
impulses, and muscle contraction. Calcitonin is a hormone
secreted by the thyroid gland and works opposite of
parathormone to reduce serum calcium and keep calcium in the
bones. Calcitonin does not have a direct effect on intracellular
osmolarity.
Which electrolyte found in intracellular fluid would the nurse
consider most important?
ANS: Potassium
Rationale: The concentration of potassium is greater inside the
cell and is important in establishing a membrane potential, a
,critical factor in the cell's ability to function. Sodium is the most
abundant cation of the extracellular compartment, not the
intracellular compartment. Calcium is the most abundant
electrolyte in the body; 99% is concentrated in the teeth and
bones, and only 1% is available for bodily functions. Chloride is
an extracellular, not intracellular, anion.
An infant with a 3-day history of decreased fluid intake and
diarrhea is admitted with dehydration and lethargy. Which
explanation would the nurse give the parent for the infant's rapid
deterioration?
ANS: The extracellular fluid requirement per unit of body
weight is greater in infants than in adults.
Rationale: Complications of fluid loss occur much more rapidly
in infants compared with children and adults because
extracellular body fluid represents 45% of the body at birth,
25% at 2 years of age, and 20% at maturity. Another
measurement is fluid's percentage of total body weight, which is
80% at birth, 63% at 3 years, and approximately 60% at 12
years. Cellular metabolism in children is stable, but its rate is
higher than that in adults. The proportion of total body water in
children (up to 2 years) is greater than it is in adults. Renal
function is immature through the second year of life, not until
school age, which makes it more difficult to maintain fluid
balance.
Which rationale supports the nurse's instruction that a client with
chronic kidney disease is to avoid all salt substitutes?
, ANS: Salt substitutes contain potassium, which must be limited
to prevent abnormal heartbeats.
Rationale Salt substitutes usually contain potassium, which can
lead to hyperkalemia; dysrhythmias are associated with
hyperkalemia. Chronic kidney disease already places the client
at a higher risk for hyperkalemia because of poor elimination of
fluids and electrolytes. Sodium, not salt substitutes, in the diet
causes retention of fluid. Salt substitutes do not contain
substances that influence blood urea nitrogen and creatinine
levels; these are the result of protein metabolism. There is not a
substance in the salt substitute that interferes with capillary
membrane transfer. Anasarca is extensive fluid in the tissues
throughout the body and more extensive than typical edema.
Which explanation would the nurse include when teaching a
client with heart failure about the reason for a low-sodium diet?
ANS: Decreased fluid retention
Rationale: The purpose of a low-sodium diet for clients with
heart failure is to decrease fluid retention. Clients with heart
failure may or may not need weight loss, but a low-sodium diet
will not help with weight control. Although sodium restriction
may lower blood pressure in clients with hypertension, because
of the Frank-Starling law, lower sodium intake may lead to
improved cardiac output and higher blood pressures in clients
with heart failure. Dietary sodium intake plays very little role in
serum sodium levels (high serum sodium levels is called
hypernatremia), which are controlled by multiple hormonal
Elsevier Quizzes Questions With Complete Solutions
Which cation regulates intracellular osmolarity?
ANS: Potassium
Rationale: A decrease in serum potassium causes a decrease in
the cell wall pressure gradient and results in water moving out of
the cell. Besides intracellular osmolarity regulation, potassium
also regulates metabolic activities, transmission and conduction
of nerve impulses, cardiac conduction, and smooth and skeletal
muscle contraction. Sodium is the most abundant extracellular
cation that regulates serum osmolarity as well as nerve impulse
transmission and acid-base balance. Calcium is an extracellular
cation necessary for bone and teeth formation, blood clotting,
hormone secretion, cardiac conduction, transmission of nerve
impulses, and muscle contraction. Calcitonin is a hormone
secreted by the thyroid gland and works opposite of
parathormone to reduce serum calcium and keep calcium in the
bones. Calcitonin does not have a direct effect on intracellular
osmolarity.
Which electrolyte found in intracellular fluid would the nurse
consider most important?
ANS: Potassium
Rationale: The concentration of potassium is greater inside the
cell and is important in establishing a membrane potential, a
,critical factor in the cell's ability to function. Sodium is the most
abundant cation of the extracellular compartment, not the
intracellular compartment. Calcium is the most abundant
electrolyte in the body; 99% is concentrated in the teeth and
bones, and only 1% is available for bodily functions. Chloride is
an extracellular, not intracellular, anion.
An infant with a 3-day history of decreased fluid intake and
diarrhea is admitted with dehydration and lethargy. Which
explanation would the nurse give the parent for the infant's rapid
deterioration?
ANS: The extracellular fluid requirement per unit of body
weight is greater in infants than in adults.
Rationale: Complications of fluid loss occur much more rapidly
in infants compared with children and adults because
extracellular body fluid represents 45% of the body at birth,
25% at 2 years of age, and 20% at maturity. Another
measurement is fluid's percentage of total body weight, which is
80% at birth, 63% at 3 years, and approximately 60% at 12
years. Cellular metabolism in children is stable, but its rate is
higher than that in adults. The proportion of total body water in
children (up to 2 years) is greater than it is in adults. Renal
function is immature through the second year of life, not until
school age, which makes it more difficult to maintain fluid
balance.
Which rationale supports the nurse's instruction that a client with
chronic kidney disease is to avoid all salt substitutes?
, ANS: Salt substitutes contain potassium, which must be limited
to prevent abnormal heartbeats.
Rationale Salt substitutes usually contain potassium, which can
lead to hyperkalemia; dysrhythmias are associated with
hyperkalemia. Chronic kidney disease already places the client
at a higher risk for hyperkalemia because of poor elimination of
fluids and electrolytes. Sodium, not salt substitutes, in the diet
causes retention of fluid. Salt substitutes do not contain
substances that influence blood urea nitrogen and creatinine
levels; these are the result of protein metabolism. There is not a
substance in the salt substitute that interferes with capillary
membrane transfer. Anasarca is extensive fluid in the tissues
throughout the body and more extensive than typical edema.
Which explanation would the nurse include when teaching a
client with heart failure about the reason for a low-sodium diet?
ANS: Decreased fluid retention
Rationale: The purpose of a low-sodium diet for clients with
heart failure is to decrease fluid retention. Clients with heart
failure may or may not need weight loss, but a low-sodium diet
will not help with weight control. Although sodium restriction
may lower blood pressure in clients with hypertension, because
of the Frank-Starling law, lower sodium intake may lead to
improved cardiac output and higher blood pressures in clients
with heart failure. Dietary sodium intake plays very little role in
serum sodium levels (high serum sodium levels is called
hypernatremia), which are controlled by multiple hormonal
