BIOS 256 EXAM 3 CERTIFICATION REVIEW
SET 2026 ANSWERS GUARANTEED PASS
⫸ infant body water content Answer: 73% or more water (low body fat,
low bone mass)
⫸ body water content in men Answer: 60%
⫸ body water content in women Answer: 50% (more fat content and
less muscle mass than men)
⫸ body water content in old age Answer: declines to 45%
⫸ extracellular fluid Answer: blood plasma and interstitial fluid (fluid
outside the cell)
⫸ nonelectrolytes Answer: solutions made by molecules that dissolve in
water, but do not dissociate; do not conduct electricity
⫸ electrolytes Answer: dissociate in water to ions and include inorganic
salts, acids and bases, and some proteins. Have greater osmotic power
because they dissociate in water and contribute at least two particles to
solutions.
,⫸ major cation in extracellular fluid Answer: Sodium (Na+)
⫸ major anion in extracellular fluid Answer: Chloride (Cl-)
⫸ major cation in intracellular fluid Answer: Potassium (K+)
⫸ major anion in intracellular fluid Answer: Phosphate
⫸ where are soluble proteins more often found? Answer: Cells contain
substantially more soluble proteins than extracellular fluids.
⫸ most abundant solutes in body fluid Answer: electrolytes, but
proteins and some nonelectrolytes account for 60-97% of dissolved
solutes.
⫸ fluid movement Answer: Anything that changes solute concentration
in any compartment leads to net water flows.
⫸ substance movement into intracellular fluid Answer: Substances must
pass through both the plasma and interstitial fluid in order to reach the
intracellular fluid, and exchanges between these compartments occur
almost continuously, leading to compensatory shifts from one
compartment to another.
,⫸ exchanges between plasma and interstitial fluid Answer: occur across
capillaries, with hydrostatic pressure forcing nearly protein-free fluid to
the IF, followed by nearly complete reabsorption into the blood from the
IF.
⫸ exchanges between interstitial fluid and intracellular fluid Answer:
dependent on the exact permeabilities of the membrane; two-way water
flow is substantial, but ion movements are restricted, and nutrients,
respiratory gases, and wastes typically occur in one direction.
⫸ maintaining proper hydration Answer: water intake must equal water
output
⫸ how does water enter the body? Answer: through ingested liquids and
food, but is also produced by cellular metabolism
⫸ how does water leave the body? Answer: evaporative loss from lungs
and skin (insensible water loss), sweating, defecation, and urination
⫸ thirst mechanism Answer: triggered by a decrease in plasma
osmolality, which results in a dry mouth and excites the hypothalamic
thirst center.
⫸ how is thirst quenched? Answer: as the mucosa of the mouth is
moistened and continues with distention of the stomach and intestines,
resulting in inhibition of the hypothalamic thirst center
, ⫸ obligatory water loss Answer: insensible water losses, water lost with
food residues and feces, and a minimum 500 ml sensible water loss in
urine, due to the demand to flush urine solutes
⫸ solute concentration and volume of urine depend on_____ Answer:
fluid intake, diet, and water losses by other routes
⫸ Antidiuretic hormone (ADH) Answer: The amount of water
reabsorbed in the renal collecting ducts is proportional to ADH release
⫸ low ADH levels Answer: most water in the collecting ducts is not
reabsorbed, resulting in large quantities of dilute urine.
⫸ high ADH levels Answer: filtered water is reabsorbed, resulting in a
lower volume of concentrated urine.
⫸ ADH secretion Answer: promoted or inhibited by the hypothalamus
in response to changes in solute concentration of extracellular fluid,
large changes in blood volume or pressure, or vascular baroreceptors
⫸ dehydration Answer: occurs when water output exceeds water intake
and may lead to weight loss, fever, mental confusion, or hypovolemic
shock
⫸ hypotonic hydration Answer: a result of renal insufficiency, or intake
of an excessive amount of water very quickly.
SET 2026 ANSWERS GUARANTEED PASS
⫸ infant body water content Answer: 73% or more water (low body fat,
low bone mass)
⫸ body water content in men Answer: 60%
⫸ body water content in women Answer: 50% (more fat content and
less muscle mass than men)
⫸ body water content in old age Answer: declines to 45%
⫸ extracellular fluid Answer: blood plasma and interstitial fluid (fluid
outside the cell)
⫸ nonelectrolytes Answer: solutions made by molecules that dissolve in
water, but do not dissociate; do not conduct electricity
⫸ electrolytes Answer: dissociate in water to ions and include inorganic
salts, acids and bases, and some proteins. Have greater osmotic power
because they dissociate in water and contribute at least two particles to
solutions.
,⫸ major cation in extracellular fluid Answer: Sodium (Na+)
⫸ major anion in extracellular fluid Answer: Chloride (Cl-)
⫸ major cation in intracellular fluid Answer: Potassium (K+)
⫸ major anion in intracellular fluid Answer: Phosphate
⫸ where are soluble proteins more often found? Answer: Cells contain
substantially more soluble proteins than extracellular fluids.
⫸ most abundant solutes in body fluid Answer: electrolytes, but
proteins and some nonelectrolytes account for 60-97% of dissolved
solutes.
⫸ fluid movement Answer: Anything that changes solute concentration
in any compartment leads to net water flows.
⫸ substance movement into intracellular fluid Answer: Substances must
pass through both the plasma and interstitial fluid in order to reach the
intracellular fluid, and exchanges between these compartments occur
almost continuously, leading to compensatory shifts from one
compartment to another.
,⫸ exchanges between plasma and interstitial fluid Answer: occur across
capillaries, with hydrostatic pressure forcing nearly protein-free fluid to
the IF, followed by nearly complete reabsorption into the blood from the
IF.
⫸ exchanges between interstitial fluid and intracellular fluid Answer:
dependent on the exact permeabilities of the membrane; two-way water
flow is substantial, but ion movements are restricted, and nutrients,
respiratory gases, and wastes typically occur in one direction.
⫸ maintaining proper hydration Answer: water intake must equal water
output
⫸ how does water enter the body? Answer: through ingested liquids and
food, but is also produced by cellular metabolism
⫸ how does water leave the body? Answer: evaporative loss from lungs
and skin (insensible water loss), sweating, defecation, and urination
⫸ thirst mechanism Answer: triggered by a decrease in plasma
osmolality, which results in a dry mouth and excites the hypothalamic
thirst center.
⫸ how is thirst quenched? Answer: as the mucosa of the mouth is
moistened and continues with distention of the stomach and intestines,
resulting in inhibition of the hypothalamic thirst center
, ⫸ obligatory water loss Answer: insensible water losses, water lost with
food residues and feces, and a minimum 500 ml sensible water loss in
urine, due to the demand to flush urine solutes
⫸ solute concentration and volume of urine depend on_____ Answer:
fluid intake, diet, and water losses by other routes
⫸ Antidiuretic hormone (ADH) Answer: The amount of water
reabsorbed in the renal collecting ducts is proportional to ADH release
⫸ low ADH levels Answer: most water in the collecting ducts is not
reabsorbed, resulting in large quantities of dilute urine.
⫸ high ADH levels Answer: filtered water is reabsorbed, resulting in a
lower volume of concentrated urine.
⫸ ADH secretion Answer: promoted or inhibited by the hypothalamus
in response to changes in solute concentration of extracellular fluid,
large changes in blood volume or pressure, or vascular baroreceptors
⫸ dehydration Answer: occurs when water output exceeds water intake
and may lead to weight loss, fever, mental confusion, or hypovolemic
shock
⫸ hypotonic hydration Answer: a result of renal insufficiency, or intake
of an excessive amount of water very quickly.
