1
BIOS256: Exam 3 Review Questions
and Answers (100% Correct
Answers) Already Graded A+
65% ICF; 35% ECF Ans: Major fluid compartments of the body
consist of what?
© 2026 Assignment
Thirst Ans: mainly governs fluid intake
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Expert
Dehydration Ans: Reduces blood volume and blood pressure,
increases blood osmolarity.
urine Ans: Only way to control water output significantly is
through variation in what?
Kidneys Ans: cannot replace water or electrolytes à can only
slow the rate of water and electrolyte loss
Na+ reabsorption Ans: Changes in urine volume linked to
adjustments in ______________, when excreted, water follows
more; slows Ans: If osmolarity rises and/or blood volume
falls, ________ ADH is secreted, and it ____________ these trends
inhibited; less; increases; reversed Ans: If osmolarity falls
and/or blood volume rises, ADH release is _______________, so
tubules reabsorb ______________ water, urine output
______________, and these trends are ______________.
Physiological functions of electrolytes Ans: •Control osmosis
between different fluid compartments of the body
, 2
•Can carry electric current as they are charged molecules
•Help maintain acid/base balance of tissues & blood
•Can serve as cofactors that are involved in metabolic
reactions
•Serve independent functions in other organ systems
Na+, K+, Ca2+, Mg2+, and H+ Ans: They are the major cations
© 2026 Assignment
Cl−, HCO3− (bicarbonate), and PO43− (phosphate) Ans: They
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are the major anions
Expert
Sodium Ans: Most abundant cation in the extracellular fluid
(ECF)
Calcium Ans: Most abundant mineral in the body, stored
mostly in the bones and teeth.
Potassium Ans: Most abundant cation in the intracellular
fluid (ICF)
Bicarbonate Ans: Anion in blood plasma can be exchanged
with chloride ions through chloride shift.
Hydrogen ions (H+) Ans: pH of a solution is determined
solely by what ion?
Acids Ans: Any chemical that donates H+ in solution
hydrochloric acid (HCl) Ans: A strong acid such as
________________ ionizes freely. Gives up most of its H+,
Markedly lowers pH of a solution
, 3
carbonic acid (H2CO3) Ans: Weak acids like _________________
ionize only slightly. Keeps most H+ chemically bound, Does
not affect pH much
Bases Ans: Any chemical that accepts H+ in a solution
hydroxide ion (OH−) Ans: Strong bases, such as the
__________________, have a strong tendency to bind H+,
markedly raising pH
© 2026 Assignment
bicarbonate ion (HCO3−) Ans: Weak bases, such as the
___________________, bind less of the available H+ and have less
effect on pH
Guru01 - Stuvia
Expert
Buffer Ans: any mechanism that resists changes in pH by
converting strong acids or bases to weak one
Physiological buffer (Urinary and Respiratory systems) Ans:
Organ system that controls output of acids, bases, or CO2
Urinary system Ans: buffers greatest quantity of acid or base
Respiratory system Ans: buffers within minutes. Cannot alter
pH as much as the urinary system
Chemical buffer Ans: A substance that binds H+ and removes
it from solution as its concentration begins to rise or releases
H+ into solution as its concentration falls. •Restores normal
pH in fractions of a second
bicarbonate, phosphate, hemoglobin, and protein systems
Ans: They are the major chemical buffers
Bicarbonate Buffer System Ans: •Converting strong acids and
strong bases into weak acids and weak bases
BIOS256: Exam 3 Review Questions
and Answers (100% Correct
Answers) Already Graded A+
65% ICF; 35% ECF Ans: Major fluid compartments of the body
consist of what?
© 2026 Assignment
Thirst Ans: mainly governs fluid intake
Guru01 - Stuvia
Expert
Dehydration Ans: Reduces blood volume and blood pressure,
increases blood osmolarity.
urine Ans: Only way to control water output significantly is
through variation in what?
Kidneys Ans: cannot replace water or electrolytes à can only
slow the rate of water and electrolyte loss
Na+ reabsorption Ans: Changes in urine volume linked to
adjustments in ______________, when excreted, water follows
more; slows Ans: If osmolarity rises and/or blood volume
falls, ________ ADH is secreted, and it ____________ these trends
inhibited; less; increases; reversed Ans: If osmolarity falls
and/or blood volume rises, ADH release is _______________, so
tubules reabsorb ______________ water, urine output
______________, and these trends are ______________.
Physiological functions of electrolytes Ans: •Control osmosis
between different fluid compartments of the body
, 2
•Can carry electric current as they are charged molecules
•Help maintain acid/base balance of tissues & blood
•Can serve as cofactors that are involved in metabolic
reactions
•Serve independent functions in other organ systems
Na+, K+, Ca2+, Mg2+, and H+ Ans: They are the major cations
© 2026 Assignment
Cl−, HCO3− (bicarbonate), and PO43− (phosphate) Ans: They
Guru01 - Stuvia
are the major anions
Expert
Sodium Ans: Most abundant cation in the extracellular fluid
(ECF)
Calcium Ans: Most abundant mineral in the body, stored
mostly in the bones and teeth.
Potassium Ans: Most abundant cation in the intracellular
fluid (ICF)
Bicarbonate Ans: Anion in blood plasma can be exchanged
with chloride ions through chloride shift.
Hydrogen ions (H+) Ans: pH of a solution is determined
solely by what ion?
Acids Ans: Any chemical that donates H+ in solution
hydrochloric acid (HCl) Ans: A strong acid such as
________________ ionizes freely. Gives up most of its H+,
Markedly lowers pH of a solution
, 3
carbonic acid (H2CO3) Ans: Weak acids like _________________
ionize only slightly. Keeps most H+ chemically bound, Does
not affect pH much
Bases Ans: Any chemical that accepts H+ in a solution
hydroxide ion (OH−) Ans: Strong bases, such as the
__________________, have a strong tendency to bind H+,
markedly raising pH
© 2026 Assignment
bicarbonate ion (HCO3−) Ans: Weak bases, such as the
___________________, bind less of the available H+ and have less
effect on pH
Guru01 - Stuvia
Expert
Buffer Ans: any mechanism that resists changes in pH by
converting strong acids or bases to weak one
Physiological buffer (Urinary and Respiratory systems) Ans:
Organ system that controls output of acids, bases, or CO2
Urinary system Ans: buffers greatest quantity of acid or base
Respiratory system Ans: buffers within minutes. Cannot alter
pH as much as the urinary system
Chemical buffer Ans: A substance that binds H+ and removes
it from solution as its concentration begins to rise or releases
H+ into solution as its concentration falls. •Restores normal
pH in fractions of a second
bicarbonate, phosphate, hemoglobin, and protein systems
Ans: They are the major chemical buffers
Bicarbonate Buffer System Ans: •Converting strong acids and
strong bases into weak acids and weak bases
