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lover lover
wrote...
Posts: 545
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6 years ago
Which type of muscle cell exhibits a longer refractory period?
 
  A.  Cardiac muscle cell
  B.  Skeletal muscle cell



(Question 2) To initiate a cardiac muscle cell contraction, calcium
 
  A. binds to calmodulin.
  B. binds to troponin.
  C. binds to actin.
  D. binds to the Z-disc.
  E. binds to tropomyosin.



(Question 3) Like skeletal muscle cells, cardiac muscle cells have an absolute refractory period prior to repolarization.
 
  Fill in the blank with correct word.



(Question 4) The time that starts when a muscle cell is depolarized and ends when it is able to be restimulated is the __________ period.
 
  Fill in the blank with correct word.



(Question 5) As with action potentials in other types of cells, the repolarization of cardiac muscle cells involves the
 
  A. entrance of calcium through voltage-gated channels.
  B. exit of potassium through voltage-gated channels.
  C. entrance of sodium through voltage-gated channels.
  D.  binding of ACh to ACh receptor.
  E. simultaneous closure of sodium channels and opening of calcium channels.



(Question 6) Most of the calcium that triggers contraction of cardiac muscle comes
 
  A. into the cell through leakage channels in the sarcolemma.
  B. into the cell through voltage-gated channels in the sarcolemma.
  C. from the sarcoplasmic reticulum of the cell.
  D. from the Golgi apparatus of the cell.



(Question 7) What is the sequence of events in the transmission of an impulse through the heart muscle?
 
  a: AV node
   b: AV bundle
   c: SA node
   d: Through the atria
   e: Through the ventricles
   f: Bundle branches
   g: Purkinje fibers
  A. c, d, a, b, f, g, e
  B. d, b, a, c, f, g, e
  C. b, a, d, c, f, g, e
  D. f, g, d, c, b, a, e
  E. c, d, a, f, b, g, e



(Question 8) At the AV node of the conduction system, the action potential is
 
  A. rapidly advanced due to the cells being large and well connected by gap junctions.
  B. rapidly advanced due to the cells being small and well insulated by myelin.
  C. delayed due to the cells being small and having few gap junctions.
  D. delayed due to the cells being large and having many leakage channels.



(Question 9) During the plateau phase of a cardiac muscle cell's action potential, the membrane stays
 
  A. depolarized as potassium exits and calcium enters.
  B. depolarized as potassium enters and calcium exits.
  C. repolarized as sodium enters and calcium exits.
  D. hyperpolarized as sodium and calcium exit.
  E. hyperpolarized as potassium enters and calcium exits.



(Question 10) The membrane of a contractile cardiac muscle cell contains
 
  A. no calcium pumps.
  B. calcium pumps that move calcium out of the cell.
  C. calcium pumps that move calcium into the cell.
  D. calcium pumps that open and allow calcium to diffuse down its concentration gradient to reach equilibrium.
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Replies
wrote...
6 years ago
1) A

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2) B

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3) TRUE

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4) refractory

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5) B

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6) C

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7) A

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8) C

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9) A

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10) B
lover Author
wrote...
6 years ago
This is very helpful, my teacher this year is not good
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