Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
Multiple Choice Questions
1) The two organs that play an important role in maintaining acid-base balance
are the
A) liver and gallbladder.
B) liver and kidneys.
C) heart and lungs.
D) lungs and kidneys.
E) heart and liver.
Answer: D
2) Intracellular fluid (ICF) is found only within
A) blood vessels.
B) lymph.
C) the cells of the body.
D) the interstitial space.
E) the cerebrospinal fluid.
Answer: C
3) Substances that can carry electrical current across cell membranes are called
A) electrons.
B) electrolytes.
C) nonelectrolytes.
D) osmoregulators.
E) buffers.
Answer: B
4) Homeostatic mechanisms that monitor and adjust the composition of body
fluids respond to
changes in the ________ fluid.
A) lymphatic
B) intracellular
C) plasma
D) extracellular
E) cerebrospinal
Answer: D
5) In an adult female, the body consists of about ________ percent water.
A) 60
B) 50
1
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
C) 40
D) 70
E) 80
Answer: B
6) All of the following are components of ECF except
A) cerebrospinal fluid.
B) peritoneal fluid.
C) lymph.
D) aqueous humor.
E) RBCs.
Answer: E
7) In a lean adult male, the body consists of about ________ percent water.
A) 60
B) 90
C) 40
D) 10
E) 80
Answer: A
8) The principal cation in intracellular fluid is
A) sodium.
B) potassium.
C) calcium.
D) magnesium.
E) chloride.
Answer: B
9) The anions in highest concentration in the extracellular fluid are
A) sodium, chloride, and bicarbonate.
B) sodium, potassium, and bicarbonate.
C) sodium, potassium, and chloride.
D) proteins, bicarbonate, and chloride.
E) sodium, potassium, and phosphate.
Answer: D
10) Which hormone plays a central role in determining the rate of sodium
reabsorption and
2
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
potassium secretion?
A) ADH
B) aldosterone
C) BNP
D) ANP
E) epinephrine
Answer: B
11) Which hormone most affects the osmolarity of blood?
A) ADH
B) angiotensin II
C) PTH
D) ANP
E) epinephrine
Answer: A
12) Which hormone(s) is released by heart muscle in response to excessive
chamber volume?
A) ADH
B) aldosterone
C) PTH
D) acetylcholine
E) natriuretic peptides
Answer: E
13) In clinical estimates, ________ of total body water is in the ICF and
________ in the ECF.
A) one-tenth; nine-tenths
B) one-quarter; three-quarters
C) one-half; one-half
D) two-thirds; one-third
E) one-third; two-thirds
Answer: D
14) The release of atrial naturetic peptides from the heart will cause the body to
A) conserve sodium ions.
B) decrease ECF.
C) excrete potassium ions.
D) conserve sodium ions and decrease ECF.
E) excrete sodium ions and decrease ECF.
Answer: E
3
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
15) Angiotensin II produces a coordinated elevation in the ECF volume by all
of the following
mechanisms except
A) stimulating thirst.
B) causing the release of ADH.
C) triggering the production and secretion of aldosterone.
D) stimulating the kidneys to conserve sodium.
E) increasing PNS activity.
Answer: E
16) Aldosterone
A) is secreted in response to decreased levels of potassium in the blood.
B) promotes sodium retention in the kidneys.
C) helps decrease blood volume and lower blood pressure.
D) regulates blood calcium levels.
E) regulates water reabsorption in the kidneys.
Answer: B
17) The principal ions in extracellular fluid are sodium, chloride, and
A) potassium.
B) magnesium.
C) phosphate.
D) bicarbonate.
E) iodine.
Answer: D
18) ________ promotes water reabsorption at the kidneys and stimulates thirst.
A) ADH
B) Aldosterone
C) Calcitonin
D) Renin
E) Natriuretic peptide
Answer: A
19) The two major subdivisions of the ECF are the
A) ICF and plasma.
B) interstitial fluid and plasma.
C) lymph and plasma.
D) serous fluids and lymph.
E) interstitial fluid and CSF.
Answer: B
4
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
20) The principal ions in intracellular fluid are magnesium, phosphate and
A) sodium.
B) bicarbonate.
C) chloride.
D) calcium.
E) potassium.
Answer: E
.
21) Water molecules move across cells by
A) osmosis.
B) primary active transport.
C) secondary active transport.
D) activity of the sodium-potassium pump.
E) phagocytosis.
Answer: A
22) Which hormone does not play a role in regulating fluid and electrolyte
balance?
A) ADH
B) aldosterone
C) cortisol
D) atrial natriuretic peptide
E) B-type natriuretic peptide
Answer: C
23) When water is lost, but electrolytes are retained,
A) the osmolarity of the ECF falls.
B) osmosis moves water from the ICF to the ECF.
C) both the ECF and the ICF become more dilute.
D) there is an increase in the volume of the ICF.
E) aldosterone is secreted.
Answer: B
24) When pure water is consumed,
A) the ECF becomes hypertonic to the ICF.
B) a fluid shift occurs and the volume of the ICF decreases.
C) osmolarities of the two fluid compartments fall.
D) the volume of the ECF decreases.
E) the volume of the ICF decreases.
Answer: C
.
25) Consuming a meal high in salt will
5
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
A) drastically increase the osmolarity of the blood.
B) result in a temporary increase in blood volume.
C) decrease thirst.
D) cause hypotension.
E) activate the renin-angiotensin mechanism.
Answer: B
26) Exchange between the two main subdivisions of ECF occurs primarily at
the
A) veins.
B) muscles.
C) tissues.
D) capillaries.
E) arteries.
Answer: D
27) The typical value of water losses and gains each day is
A) 500 mL.
B) 1000 mL.
C) 1500 mL.
D) 2000 mL.
E) 2500 mL.
Answer: E
28) The most dangerous problems with electrolyte balance are caused by an
imbalance between
gains and losses of
A) calcium ions.
B) chlorine ions.
C) potassium ions.
D) sodium ions.
E) electrons.
Answer: C
29) Calcium reabsorption by the kidneys is promoted by the hormone
A) calcitonin.
B) parathyroid hormone.
C) aldosterone.
D) cortisol.
E) ADH.
Answer: B
6
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
30) To reduce brain swelling by pulling water out of brain cells, a substance can
be injected intravenously to increase the osmotic pressure of interstitial fluid.
Which of the following properties must this substance lack in order to be
effective?
A) permeable to capillary endothelium
B) nontoxic to neurons
C) permeable to brain plasma membranes
D) impermeable to brain plasma membranes
E) soluble in water
Answer: C
31) The amount of potassium excreted by the kidneys is regulated mainly by
A) ADH.
B) aldosterone.
C) parathormone.
D) atrial natriuretic peptides.
E) glucocorticoids.
Answer: B
32) Alice has been running a marathon and has only been drinking pure water.
Which electrolyte
imbalance is she likely to experience?
A) hyponatremia
B) hypernatremia
C) hypercalcemia
D) hypocalcemia
E) hyperkalemia
Answer: A
.
33) A chemical that minimizes changes in the pH of a body fluid by releasing or
binding hydrogen ion is called a(n)
A) electrolyte.
B) acid.
C) alkali.
D) compensation.
E) buffer.
Answer: E
34) Excess hydrogen ion is eliminated from the body largely by
A) sweating.
B) the kidneys.
7
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
C) the liver.
D) the feces.
E) buffers.
Answer: B
35) The primary role of the carbonic-acid-bicarbonate buffer system is to
A) buffer stomach acid.
B) buffer carbonic acid formed by carbon dioxide.
C) limit pH changes caused by metabolic and fixed acids.
D) buffer the urine.
E) increase ventilation.
Answer: C
36) A(n) ________ acid is an acid that can leave solution and enter the
atmosphere.
A) respiratory
B) volatile
C) metabolic
D) inorganic
E) fixed
Answer: B
37) The normal pH range for ECF is
A) 6.5 to 7.5.
B) 6.8 to 7.2.
C) 7 to 7.5.
D) 7.35 to 7.45.
E) 7.5 to 8.0.
Answer: D
38) When the pH ________, a state of acidosis exists.
A) rises above 7
B) falls below 7
C) falls below 6.5
D) falls below 7.35
E) rises above 7.5
Answer: D
39) A patient who has been both vomiting and having diarrhea is losing all of
the following
except ________ from his body.
A) water
8
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
B) sodium
C) bicarbonate ion
D) hydrogen ion
E) protein
Answer: E
40) When the pH rises above 7.45, a state of ________ exists.
A) apotheosis
B) alkalosis
C) ptosis
D) hydrosis
E) acidosis
Answer: B
41) Amino acids in solution contain both a negative and positive charge and
thus are termed a(n)
A) anion.
B) cation.
C) acid.
D) base.
E) zwitterion.
Answer: E
42) Which of the following is not a renal response to acidosis?
A) secretion of H+
B) increase tubule buffer activity
C) reabsorption of NaHCO3
D) release of HCl into peritubular capillary fluid
E) removal of CO2
Answer: D
43) Hypoventilation leads to
A) respiratory acidosis.
B) respiratory alkalosis.
C) metabolic acidosis.
D) metabolic alkalosis.
E) lactic acidosis.
Answer: A
44) In response to respiratory alkalosis, the
A) respiratory rate increases.
B) tidal volume increases.
C) kidneys conserve bicarbonate.
9
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
D) kidneys secrete more hydrogen ions.
E) kidneys retain more hydrogen ions.
Answer: E
45) A person with emphysema will exhibit signs of
A) chronic respiratory acidosis.
B) chronic respiratory alkalosis.
C) acute respiratory acidosis.
D) chronic metabolic acidosis.
E) metabolic alkalosis.
Answer: A
46) A person with poorly controlled diabetes mellitus will develop
A) respiratory acidosis.
B) acute respiratory alkalosis.
C) metabolic acidosis.
D) metabolic alkalosis.
E) chronic respiratory alkalosis.
Answer: C
47) Which of the following descriptions best fits the acid-base disorder
metabolic alkalosis?
A) consequence of hyperventilation (for example, in fever or mental illness)
B) consequence of prolonged vomiting
C) consequence of reduced alveolar ventilation (for example, due to COPD)
D) consequence of tissue hypoxia (for example, in ischemic conditions)
E) consequence of strenuous exercise
Answer: B
48) A person who consumes large amounts of sodium bicarbonate (baking soda)
to settle an
upset stomach risks
A) respiratory acidosis.
B) respiratory alkalosis.
C) metabolic acidosis.
D) metabolic alkalosis.
E) lactic acidosis.
Answer: D
49) Severe kidney damage, such as glomerulonephritis, often leads to
A) acute respiratory acidosis.
B) respiratory alkalosis.
C) metabolic acidosis.
10
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
D) metabolic alkalosis.
E) chronic respiratory acidosis.
Answer: C
50) Which of the following descriptions best fits the acid-base disorder
respiratory acidosis?
A) consequence of hyperventilation (for example, in fever or mental illness)
B) consequence of prolonged vomiting
C) consequence of reduced alveolar ventilation (for example, due to
emphysema)
D) consequence of tissue hypoxia (for example, in ischemic conditions)
E) consequence of strenuous exercise
Answer: C
51) When the pH of the extracellular fluid drops, the kidneys
A) excrete more hydrogen ions.
B) excrete more bicarbonate ions.
C) excrete fewer bicarbonate ions.
D) secrete more hydrogen ions and more bicarbonate ions.
E) secrete more hydrogen ions and fewer bicarbonate ions.
Answer: E
52) Which of the following descriptions best fits the acid-base disorder
respiratory alkalosis?
A) consequence of hyperventilation (for example, in fever or mental illness)
B) consequence of prolonged vomiting
C) consequence of reduced alveolar ventilation (for example, due to COPD)
D) consequence of tissue hypoxia (for example, in ischemic conditions)
E) consequence of strenuous exercise
Answer: A
53) Hypercapnia refers to elevated levels of
A) oxygen.
B) hemoglobin.
C) carbon monoxide.
D) sodium.
E) carbon dioxide.
Answer: E
54) A drowning victim will likely experience a period of ________ until
resuscitation begins.
A) acute respiratory acidosis
B) acute respiratory alkalosis
11
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
C) chronic respiratory alkalosis
D) metabolic acidosis
E) metabolic alkalosis
Answer: A
55) Extreme losses of bicarbonate ions, such as in diarrhea, will cause
A) acute respiratory acidosis.
B) chronic respiratory acidosis.
C) respiratory alkalosis.
D) metabolic acidosis.
E) metabolic alkalosis.
Answer: D
56) All of the following are examples of compensatory mechanisms that would
occur as a result
of metabolic acidosis except
A) buffer systems accept H+.
B) kidneys secrete H+.
C) kidneys retain H+.
D) kidneys generate bicarbonate.
E) respiratory rate increases.
Answer: C
57) Administration of a medication in the elderly can result in a much higher
dosage than the
clinician might intend because
A) the metabolic rate in the elderly is so high.
B) the kidneys of the elderly do not work well.
C) the elderly have less water content in the body.
D) other medications they take might enhance the concentration of another
drug.
E) they cannot regulate pH well.
Answer: C
58) Which of the following statements is false regarding fluid and electrolyte
balance?
A) Fluctuations in diet will affect babies less because they have so much water
content.
B) Older people tend to become more dehydrated.
C) Kidney functions tend to decrease as one ages.
D) Aging correlates with problems in various organ systems, which can enhance
acid-base imbalance problems.
12
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
E) A fetus obtains water and electrolytes from the maternal bloodstream.
Answer: A
Figure-Based Questions:
1) Mg2+ and K+ are found in higher concentrations in the (intracellular,
extracellular) fluid, whereas Na+ and Cl- are found in higher concentrations in
the (intracellular, extracellular) fluid. (Figure 27-2)
A) intracellular; extracellular
B) extracellular; intracellular
Answer: A
Mg2+ and K+ are found in higher concentrations in the (intracellular,
extracellular) fluid, whereas Na+ and Cl- are found in higher concentrations in
the (intracellular, extracellular) fluid. ?
2) What is a serious condition that could occur if the potassium ion
concentration is >7 mEq/L? (Figure 27-7)
A) muscle weakness leading to paralysis
B) increased urine volume
C) respiratory depression
D) acidosis
E) cardiac arrhythmias
Answer: E
13
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
3) In which body fluid do the phosphate and protein buffer systems help regulate the pH?
(Figure 27-10)
A) intracellular fluid
B) extracellular fluid
C) blood plasma
D) cerebrospinal fluid
Answer: A
4) What is the kidney's response to alkalosis caused by the removal of H+?
(Figure 27-14)
A) secrete H+ and conserve HCO3B) conserve H+ and secrete HCO3C) remove CO2
D) convert carbonic acid to water
E) secrete sodium ions and conserve potassium ions
Answer: B
5) How do the lungs respond to metabolic acidosis? (Figure 27-16)
A) lungs increase respiratory rate
B) lungs decrease respiratory rate
C) lungs secrete H+
D) lungs conserve H+
E) lungs convert carbonic acid to water
14
Fundamentals of Anatomy and Physiology, 11e (Martini)Chapter 27 Fluid,
Electrolyte, and Acid-Base Balance
Answer: A
Essay Questions
1) The maintenance of normal volume and composition of extracellular and
intracellular fluids is vital to life. List and briefly describe the kinds of
homeostasis involved.
Answer: Three types of homeostasis are involved: fluid balance, electrolyte
balance, and acid base balance. Fluid balance means that the total quantity of
body water remains almost constant and that the distribution between the ICF
and ECF are normal. Electrolyte balance implies the same thing for ions. Acidbase balance means that the pH of the ECF is maintained in the range
of 7.35 to 7.45, and that gains or losses of hydrogen ion as a consequence of
metabolism are followed by equivalent losses or gains so as to maintain
constant buffer reserves.
2) Fred has chronic emphysema. Blood tests show that his pH is low but
almost normal but his bicarbonate levels are elevated significantly. How
can this be? What would urinalysis show?
Answer: Emphysema limits alveolar ventilation, leading to increased carbon
dioxide in Fred's body. Since Fred's condition is chronic (long term) his body
has compensated for the excess carbonic acid (the result of hypercapnia due to
poor ventilation) by increasing the amount of bicarbonate to match the elevated
level of hydrogen ion. This compensation for respiratory acidosis was
accomplished by the kidney's secretion of hydrogen ion both in the PCT and
DCT and the retention of bicarbonate from the elevated carbonic acid.
Urinalysis would indicate a very low pH and high levels of ammonia, produced
by the distal tubule to absorb the secreted hydrogen ion.
3) Why does potassium concentration rise in patients with acidosis? What
is this called? What effects does it have?
Answer: When pH is low, hydrogen ion levels in the blood are high and also in
the interstitial and peritubular fluid. Hydrogen ion competes with potassium ion
for the sodium countercurrent exchanger in the tubules. As hydrogen ion
secretion rises (which compensates for the acidosis),
potassium is retained and hyperkalemia develops. If severe enough, muscle
cramps and cardiac arrhythmias result.
15