Maintenance of the Body
(Some questions have more than one correct answer. Select the best
answer or answers from the choices given.)
Body water content is greatest in
Potassium, magnesium, and phosphate ions are the predominant
Sodium balance is regulated primarily by control of amount(s)
excreted in urine,
lost in perspiration,
Water balance is regulated by control of amount(s) (use choices
in question 3).
Answer questions 5 through 10 by choosing responses from the
Explain the relationship of the following to renal secretion and
excretion of hydrogen ions: (a) plasma carbon dioxide levels, (b)
phosphate, and (c) sodium bicarbonate reabsorption.
List several factors that place newborn babies at risk for acid-base
and Clinical Application
Mr. Jessup, a 55-year-old man, is operated on for a cerebral
tumor. About a month later, he appears at his physician’s oﬃce
complaining of excessive thirst. He claims to have been drinking
about 20 liters of water daily for the past week and says he has
been voiding nearly continuously. A urine sample is collected and
its speciﬁc gravity is reported as 1.001. What is your diagnosis of
Mr. Jessup’s problem? What connection might exist between his
previous surgery and his present problem?
For each of the following sets of blood values, name the acid-base
imbalance (acidosis or alkalosis), determine its cause (metabolic or
respiratory), decide whether the condition is being compensated,
and cite at least one possible cause of the imbalance.
: pH 7.63; P
19 mm Hg; HCO
: pH 7.22; P
30 mm Hg; HCO
Explain how emphysema and congestive heart failure can lead to
Mrs. Bush, a 70-year-old woman, is admitted to the hospital.
Her history states that she has been suﬀering from diarrhea for
three weeks. On admission, she complains of severe fatigue and
muscle weakness. A blood chemistry study yields the following
142 mEq/L; K
1.5 mEq/L; Cl
92 mEq/L; P
32 mm Hg. Which electrolytes are within normal limits? Which
are so abnormal that the patient has a medical emergency? Which
of the following represents the greatest danger to Mrs. Bush?
(a) a fall due to her muscular weakness, (b) edema, (c) cardiac
arrhythmia and cardiac arrest.
During a routine medical checkup, Candace, a 26-year-old
physiotherapy student, is surprised to hear that her blood pressure
is 180/110. She also has a rumbling systolic and diastolic abdominal
bruit (murmur) that is loudest at the mid-epigastric area. Her
physician suspects renal artery stenosis (narrowing). She orders
an abdominal ultrasound and renal artery arteriography, which
conﬁrm that Candace has a small right kidney and the distal part of
her right renal artery is narrowed by more than 70%. Her physician
prescribes diuretics and calcium channel blockers as temporary
measures, and refers Candace to a cardiovascular surgeon. Explain
the connection between Candace’s renal artery stenosis and her
hypertension. Why is her right kidney smaller than her le±? What
would you expect Candace’s blood levels of K
angiotensin II, and renin to be?
Two main substances regulated by the inﬂuence of aldosterone on
the kidney tubules.
Two substances regulated by parathyroid hormone.
Two substances secreted into the proximal convoluted tubules in
exchange for sodium ions.
Part of an important chemical buﬀer system in plasma.
Two ions produced during catabolism of glutamine.
Substance regulated by ADH’s eﬀects on the renal tubules.
Which of the following factors will enhance ADH release?
increase in ECF volume,
decrease in ECF volume,
decrease in ECF osmolality,
increase in ECF osmolality.
²e pH of blood varies directly with
none of the above.
In an individual with metabolic acidosis, a clue that the
respiratory system is compensating is provided by
low blood bicarbonate levels,
slow, shallow breathing.
Short Answer Essay Questions
Name the body ﬂuid compartments, noting their locations and
the approximate ﬂuid volume in each.
Describe the thirst mechanism, indicating how it is triggered and
Explain why and how ECF osmolality is maintained.
Explain why and how sodium balance, ECF volume, and blood
pressure are jointly regulated.
Describe the role of the respiratory system in controlling acid-
Explain how the chemical buﬀer systems resist changes in pH.