PHGY 216 Final Exam Questions With
Correct Answers
Water |Balance |- |CORRECT |ANSWER✔✔-- |Every |cell |in |the |body |requires |a |well-regulated |
environment |in |order |to |survive |and |function
- |Body |water |plays |a |large |role |in |creating |this |environment, |which |is |comprised |of |
intracellular |and |extracellular |fluid
- |When |we |talk |about |the |major |body |compartments |for |water |(fluid) |there |are |three |key |
pools: |ICF, |plasma, |and |interstitial |fluid, |which |remain |distinct |due |to |the |presence |of
|"barriers" |between |them
Intracellular |Fluid |(ICF) |- |CORRECT |ANSWER✔✔-This |is |the |fluid |within |the |cells |and |comprises
|about |two |thirds |of |total |body |fluid
Extracellular |Fluid |(ECF) |- |CORRECT |ANSWER✔✔-- |This |is |the |fluid |surrounding |the |cells |which |
includes |the |plasma, |the |interstitial |fluid, |lymph, |and |transcellular |fluid |(such |as |cerebrospinal |
fluid) |and |comprises |about |one |third |of |total |body |fluid
- |The |plasma |is |about |one |fifth |of |the |ECF, |the |interstitial |fluid |is |about |four |fifths |of |the |ECF, |
and |the |lymph |and |the |transcellular |fluid |are |considered |negligible
Transcellular |Fluid |- |CORRECT |ANSWER✔✔-The |portion |of |total |body |water |contained |within |
epithelial |lined |spaces
Barriers |Between |Body-Fluid |Compartments |- |CORRECT |ANSWER✔✔-- |Several |barriers |
separate |the |body-fluid |compartments
- |This |limits |the |movement |of |water |and |solutes |between |the |various |compartments |to |
differing |degrees
,Barriers |Between |the |Plasma |and |Interstitial |Fluid |- |CORRECT |ANSWER✔✔-- |The |plasma |and |
the |interstitial |fluid |are |separated |by |the |blood |vessel |walls
- |At |the |level |of |the |capillaries, |water |and |everything |else |in |the |plasma |(except |proteins) |can |
freely |exchange |with |the |interstitial |fluid
- |Because |of |this, |the |composition |of |the |plasma |and |the |interstitial |fluid |are |essentially |
identical, |except |for |the |plasma |protein
- |Consequently, |any |change |in |one |of |these |compartments |is |quickly |reflected |in |the |other |
compartments
Barriers |Between |the |Intracellular |Fluid |and |the |ECF |- |CORRECT |ANSWER✔✔-- |This |barrier |is |
the |plasma |membrane |that |surrounds |each |cell |in |the |body
- |The |ICF |contains |proteins |that |do |not |exchange |with |the |ECF
- |There |is |an |unequal |distribution |of |ions |across |this |barrier |because |the |barrier |does |not |
allow |the |passive |movement |of |either |ICF |or |ECF |constituents |across |the |plasma |membrane, |
preventing |them |from |equilibrating |through |diffusion
ECF |Volume |and |Osmolarity |- |CORRECT |ANSWER✔✔-- |All |exchanges |of |water |and |other |
constituents |between |the |ICF |and |the |external |world |are |dependent |upon |the |ECF
- |Even |though |cells |tightly |regulate |their |own |ICF, |it |can |be |said |that |overall |control |of |fluid |
balance |is |dependent |upon |regulating |the |ECF
- |In |order |to |maintain |fluid |balance |in |the |body |the |ECF |volume |and |osmolarity |are |regulated
ECF |Volume |- |CORRECT |ANSWER✔✔-- |This |is |closely |regulated |to |maintain |blood |pressure
- |The |maintenance |of |salt |balance |is |important |in |the |long-term |regulation |of |ECF |volume
ECF |Osmolarity |- |CORRECT |ANSWER✔✔-- |This |is |closely |regulated |to |prevent |the |swelling |or |
shrinkage |of |cells
Control |of |ECF |Volume |- |CORRECT |ANSWER✔✔-- |ECF |volume |directly |influences |blood |
pressure |by |changing |plasma |volume
,- |Increasing |ECF |volume |will |increase |plasma |volume |,and |thus |increase |arterial |blood |
pressure
- |Consequently |there |are |mechanisms |in |place |to |adjust |blood |pressure |until |the |ECF |volume |
is |returned |to |normal |values
- |There |are |short |term |control |factor |including |the |baroreceptor |reflex |and |fluid |shifts
- |There |are |long |term |control |factors |including |fluid |input |and |output
The |Baroreceptor |Reflex |- |CORRECT |ANSWER✔✔-- |Baroreceptors |are |mechanoreceptor |that |
are |located |in |the |carotid |artery |and |the |aortic |arch |(areas |within |major |arteries |of |the |body), |
and |they |detect |changes |in |arterial |blood |pressure
- |Through |the |effects |of |the |autonomic |nervous |system |on |the |heart |and |blood |vessels, |teh |
baroreceptor |reflex |regulates |blood |pressure
- |When |pressure |falls |too |low, |cardiac |output |and |total |peripheral |resistance |will |increase |to |
raise |blood |pressure
- |When |blood |pressure |rises |above |normal, |both |decrease |to |reduce |blood |pressure
Total |Peripheral |Resistance |- |CORRECT |ANSWER✔✔-- |The |resistance |to |blood |flow |due |to |the |
constriction |of |blood |vessels
- |Higher |total |peripheral |resistance |leads |to |increased |blood |pressure
Cardiac |Output |- |CORRECT |ANSWER✔✔-The |amount |of |blood |pumped |by |the |heart |per |
minute
Fluid |Shifts |- |CORRECT |ANSWER✔✔-- |A |decrease |in |plasma |volume |can |temporarily |be |
compensated |for |by |a |shift |of |the |fluids |out |of |the |interstitial |compartments |to |the |plasma
- |The |opposite |is |also |true, |an |increase |in |plasma |volume |can |cause |fluid |to |shift |to |the |
interstitial |compartment
Fluid |Input/Output |- |CORRECT |ANSWER✔✔-- |The |short |term |control |mechanisms |are |only |
temporary |and |can |only |compensate |for |fairly |minor |changes |in |ECF |fluid |volumes
, - |Long-term |regulation |of |blood |pressure |is |a |primary |function |of |the |kidneys |and |the |thirst |
mechanism, |controlling |fluid |output |and |input, |respectively
- |Control |of |urine |output |by |the |kidneys |is |critical |for |long-term |regulation |of |blood |pressure
Control |of |Salt |- |CORRECT |ANSWER✔✔-- |Sodium, |and |the |anions |that |are |associated |with |it |
(mainly |chloride), |account |for |more |than |90% |of |the |ECF's |solutes
- |Whenever |salt |is |transported |across |a |membrane, |water |follows |due |to |osmosis
- |Therefore, |by |controlling |salt |levels, |ECF |volume |is |being |controlled
- |To |maintain |salt |balance, |salt |input |must |equal |salt |output
Salt |Input |- |CORRECT |ANSWER✔✔-- |Regulation |of |salt |input |is |poor |as |it |is |dependent |upon |
dietary |salt
- |It |is |necessary |on |a |daily |basis |to |replace |the |salt |lost |in |the |feces |and |sweat, |which |is |about |
0.5g/day |for |normal |activity |levels |(higher |activity |levels |will |increase |the |amount |lost |in |
sweat)
- |The |average |input |for |Canadians |is |around |3.5 |g/day
Salt |Output |- |CORRECT |ANSWER✔✔-- |The |excess |salt |must |be |eliminated, |which |occurs |in |the
|kidneys
- |The |three |pathways |to |eliminate |salt |are |in |the |feces, |sweat, |and |the |kidneys
- |The |kidneys |have |the |greatest |role |in |salt |elimination
Control |of |ECF |Osmolarity |- |CORRECT |ANSWER✔✔-- |Water |moves |down |its |concentration |
gradient |until |the |osmotic |pressure |across |a |membrane |is |equalized
- |Because |of |this, |regulating |osmolarity |is |very |important |in |preventing |changes |in |cell |volume
- |When |there |is |a |decrease |in |ECF |water |the |osmolarity |increases |and |the |ECF |is |hypertonic
- |Since |there |is |normally |a |balance |in |the |osmolarity |of |the |ICF |and |ECF, |hypertonicity |of |the |
ECF |causes |water |to |move |out |of |the |cells |into |the |ECF |until |the |osmotic |pressure |is |equalized
- |This |loss |of |water |from |cells |can |cause |them |to |shrink
Correct Answers
Water |Balance |- |CORRECT |ANSWER✔✔-- |Every |cell |in |the |body |requires |a |well-regulated |
environment |in |order |to |survive |and |function
- |Body |water |plays |a |large |role |in |creating |this |environment, |which |is |comprised |of |
intracellular |and |extracellular |fluid
- |When |we |talk |about |the |major |body |compartments |for |water |(fluid) |there |are |three |key |
pools: |ICF, |plasma, |and |interstitial |fluid, |which |remain |distinct |due |to |the |presence |of
|"barriers" |between |them
Intracellular |Fluid |(ICF) |- |CORRECT |ANSWER✔✔-This |is |the |fluid |within |the |cells |and |comprises
|about |two |thirds |of |total |body |fluid
Extracellular |Fluid |(ECF) |- |CORRECT |ANSWER✔✔-- |This |is |the |fluid |surrounding |the |cells |which |
includes |the |plasma, |the |interstitial |fluid, |lymph, |and |transcellular |fluid |(such |as |cerebrospinal |
fluid) |and |comprises |about |one |third |of |total |body |fluid
- |The |plasma |is |about |one |fifth |of |the |ECF, |the |interstitial |fluid |is |about |four |fifths |of |the |ECF, |
and |the |lymph |and |the |transcellular |fluid |are |considered |negligible
Transcellular |Fluid |- |CORRECT |ANSWER✔✔-The |portion |of |total |body |water |contained |within |
epithelial |lined |spaces
Barriers |Between |Body-Fluid |Compartments |- |CORRECT |ANSWER✔✔-- |Several |barriers |
separate |the |body-fluid |compartments
- |This |limits |the |movement |of |water |and |solutes |between |the |various |compartments |to |
differing |degrees
,Barriers |Between |the |Plasma |and |Interstitial |Fluid |- |CORRECT |ANSWER✔✔-- |The |plasma |and |
the |interstitial |fluid |are |separated |by |the |blood |vessel |walls
- |At |the |level |of |the |capillaries, |water |and |everything |else |in |the |plasma |(except |proteins) |can |
freely |exchange |with |the |interstitial |fluid
- |Because |of |this, |the |composition |of |the |plasma |and |the |interstitial |fluid |are |essentially |
identical, |except |for |the |plasma |protein
- |Consequently, |any |change |in |one |of |these |compartments |is |quickly |reflected |in |the |other |
compartments
Barriers |Between |the |Intracellular |Fluid |and |the |ECF |- |CORRECT |ANSWER✔✔-- |This |barrier |is |
the |plasma |membrane |that |surrounds |each |cell |in |the |body
- |The |ICF |contains |proteins |that |do |not |exchange |with |the |ECF
- |There |is |an |unequal |distribution |of |ions |across |this |barrier |because |the |barrier |does |not |
allow |the |passive |movement |of |either |ICF |or |ECF |constituents |across |the |plasma |membrane, |
preventing |them |from |equilibrating |through |diffusion
ECF |Volume |and |Osmolarity |- |CORRECT |ANSWER✔✔-- |All |exchanges |of |water |and |other |
constituents |between |the |ICF |and |the |external |world |are |dependent |upon |the |ECF
- |Even |though |cells |tightly |regulate |their |own |ICF, |it |can |be |said |that |overall |control |of |fluid |
balance |is |dependent |upon |regulating |the |ECF
- |In |order |to |maintain |fluid |balance |in |the |body |the |ECF |volume |and |osmolarity |are |regulated
ECF |Volume |- |CORRECT |ANSWER✔✔-- |This |is |closely |regulated |to |maintain |blood |pressure
- |The |maintenance |of |salt |balance |is |important |in |the |long-term |regulation |of |ECF |volume
ECF |Osmolarity |- |CORRECT |ANSWER✔✔-- |This |is |closely |regulated |to |prevent |the |swelling |or |
shrinkage |of |cells
Control |of |ECF |Volume |- |CORRECT |ANSWER✔✔-- |ECF |volume |directly |influences |blood |
pressure |by |changing |plasma |volume
,- |Increasing |ECF |volume |will |increase |plasma |volume |,and |thus |increase |arterial |blood |
pressure
- |Consequently |there |are |mechanisms |in |place |to |adjust |blood |pressure |until |the |ECF |volume |
is |returned |to |normal |values
- |There |are |short |term |control |factor |including |the |baroreceptor |reflex |and |fluid |shifts
- |There |are |long |term |control |factors |including |fluid |input |and |output
The |Baroreceptor |Reflex |- |CORRECT |ANSWER✔✔-- |Baroreceptors |are |mechanoreceptor |that |
are |located |in |the |carotid |artery |and |the |aortic |arch |(areas |within |major |arteries |of |the |body), |
and |they |detect |changes |in |arterial |blood |pressure
- |Through |the |effects |of |the |autonomic |nervous |system |on |the |heart |and |blood |vessels, |teh |
baroreceptor |reflex |regulates |blood |pressure
- |When |pressure |falls |too |low, |cardiac |output |and |total |peripheral |resistance |will |increase |to |
raise |blood |pressure
- |When |blood |pressure |rises |above |normal, |both |decrease |to |reduce |blood |pressure
Total |Peripheral |Resistance |- |CORRECT |ANSWER✔✔-- |The |resistance |to |blood |flow |due |to |the |
constriction |of |blood |vessels
- |Higher |total |peripheral |resistance |leads |to |increased |blood |pressure
Cardiac |Output |- |CORRECT |ANSWER✔✔-The |amount |of |blood |pumped |by |the |heart |per |
minute
Fluid |Shifts |- |CORRECT |ANSWER✔✔-- |A |decrease |in |plasma |volume |can |temporarily |be |
compensated |for |by |a |shift |of |the |fluids |out |of |the |interstitial |compartments |to |the |plasma
- |The |opposite |is |also |true, |an |increase |in |plasma |volume |can |cause |fluid |to |shift |to |the |
interstitial |compartment
Fluid |Input/Output |- |CORRECT |ANSWER✔✔-- |The |short |term |control |mechanisms |are |only |
temporary |and |can |only |compensate |for |fairly |minor |changes |in |ECF |fluid |volumes
, - |Long-term |regulation |of |blood |pressure |is |a |primary |function |of |the |kidneys |and |the |thirst |
mechanism, |controlling |fluid |output |and |input, |respectively
- |Control |of |urine |output |by |the |kidneys |is |critical |for |long-term |regulation |of |blood |pressure
Control |of |Salt |- |CORRECT |ANSWER✔✔-- |Sodium, |and |the |anions |that |are |associated |with |it |
(mainly |chloride), |account |for |more |than |90% |of |the |ECF's |solutes
- |Whenever |salt |is |transported |across |a |membrane, |water |follows |due |to |osmosis
- |Therefore, |by |controlling |salt |levels, |ECF |volume |is |being |controlled
- |To |maintain |salt |balance, |salt |input |must |equal |salt |output
Salt |Input |- |CORRECT |ANSWER✔✔-- |Regulation |of |salt |input |is |poor |as |it |is |dependent |upon |
dietary |salt
- |It |is |necessary |on |a |daily |basis |to |replace |the |salt |lost |in |the |feces |and |sweat, |which |is |about |
0.5g/day |for |normal |activity |levels |(higher |activity |levels |will |increase |the |amount |lost |in |
sweat)
- |The |average |input |for |Canadians |is |around |3.5 |g/day
Salt |Output |- |CORRECT |ANSWER✔✔-- |The |excess |salt |must |be |eliminated, |which |occurs |in |the
|kidneys
- |The |three |pathways |to |eliminate |salt |are |in |the |feces, |sweat, |and |the |kidneys
- |The |kidneys |have |the |greatest |role |in |salt |elimination
Control |of |ECF |Osmolarity |- |CORRECT |ANSWER✔✔-- |Water |moves |down |its |concentration |
gradient |until |the |osmotic |pressure |across |a |membrane |is |equalized
- |Because |of |this, |regulating |osmolarity |is |very |important |in |preventing |changes |in |cell |volume
- |When |there |is |a |decrease |in |ECF |water |the |osmolarity |increases |and |the |ECF |is |hypertonic
- |Since |there |is |normally |a |balance |in |the |osmolarity |of |the |ICF |and |ECF, |hypertonicity |of |the |
ECF |causes |water |to |move |out |of |the |cells |into |the |ECF |until |the |osmotic |pressure |is |equalized
- |This |loss |of |water |from |cells |can |cause |them |to |shrink
