BIO 392 Exam 2 Practice Exam | 39 Questions And
Answers | Verified Study Updates
1) A new action potential can be fired during the absolute refractory period
A) true
B) False ANS B)False
2) The rising phase of the action potential is due primarily to
A) Na+ flow out of the cell only.
B) Na+ flow out of the cell and K+ flow into the cell.
C) K+ flow out of the cell only.
D) Na+ flow into the cell only.
E) K+ flow into the cell only ANS D) Na+ flow into the cell only.
3) The falling phase of the action potential is due primarily to
A) K+ flow out of the cell only.
B) K+ flow into the cell only.
C) Na+ flow out of the cell only.
D) Na+ flow in the cell only.
E) Na+ flow out of the cell and K+ flow into the cell ANS A) K+ flow out of the cell only.
4) The term hyperkalemia specifically indicates too much potassium in the blood. All else being equal
hyperkalemia will bring the membrane _______ the threshold, _____ the likelihood of an action potential
being triggered.
A) away from/ decreasing
B) away from/ increasing
C) closer to/decreasing
D) closer to/increasing
E) it will not affect the membrane potential and excitability of the cell ANS D) closer to/increasing
5) Tetrodotoxin (TXX) blocks the voltage -gated Na+ channel. How will TTX influence action potentials in a
neuron?
, A) the membrane will undergo extreme hyperpolarization
B) it will not influence the neuron and action potentials will fire normally
C) action potentials will disappear immediately after applying TTX
D) action potentials will initially fire but will disappear as the Na+ concentration gradient dissipate ANS
C) action potentials will disappear immediately after applying TTX
6) Spatial summation is
A) Membrane potential produced as two or more inputs, from two or more neuron are added together.
B) Membrane potential produced as two or more inputs, occurring at different times but from the same neuron
are added together.
C) When two action potentials arriving from two neurons are added together
D) When two action potentials arriving in short succession from the same neurons are added together
E) none of the above ANS A)Membrane potential produced as two or more inputs, from two or more
neuron are added together.
7) The absolute refractory period of an action potential
A) allows the next action potential to be fired but only when the stimulus is stronger
B) ensures one-way travel down an axon and prevents summation of action potentials.
C) only prevents summation of action potentials.
D) only ensures one -way travel down an axon. ANS B) ensures one-way travel down an axon and
prevents summation of action potentials.
8) Choose which items that are correctly matched. Note that the text refers to the voltage gate as the 'activation
gate'.
A) voltage gate closed during depolarization
B) inactivation gate closed during repolarization
C) inactivation gate open during repolarization
D) voltage gate open at rest
E) All of the answers are incorrectly matched. ANS B) inactivation gate closed during repolarization
9) Autonomic motor neurons are subdivided into the
A) central and peripheral divisions.
Answers | Verified Study Updates
1) A new action potential can be fired during the absolute refractory period
A) true
B) False ANS B)False
2) The rising phase of the action potential is due primarily to
A) Na+ flow out of the cell only.
B) Na+ flow out of the cell and K+ flow into the cell.
C) K+ flow out of the cell only.
D) Na+ flow into the cell only.
E) K+ flow into the cell only ANS D) Na+ flow into the cell only.
3) The falling phase of the action potential is due primarily to
A) K+ flow out of the cell only.
B) K+ flow into the cell only.
C) Na+ flow out of the cell only.
D) Na+ flow in the cell only.
E) Na+ flow out of the cell and K+ flow into the cell ANS A) K+ flow out of the cell only.
4) The term hyperkalemia specifically indicates too much potassium in the blood. All else being equal
hyperkalemia will bring the membrane _______ the threshold, _____ the likelihood of an action potential
being triggered.
A) away from/ decreasing
B) away from/ increasing
C) closer to/decreasing
D) closer to/increasing
E) it will not affect the membrane potential and excitability of the cell ANS D) closer to/increasing
5) Tetrodotoxin (TXX) blocks the voltage -gated Na+ channel. How will TTX influence action potentials in a
neuron?
, A) the membrane will undergo extreme hyperpolarization
B) it will not influence the neuron and action potentials will fire normally
C) action potentials will disappear immediately after applying TTX
D) action potentials will initially fire but will disappear as the Na+ concentration gradient dissipate ANS
C) action potentials will disappear immediately after applying TTX
6) Spatial summation is
A) Membrane potential produced as two or more inputs, from two or more neuron are added together.
B) Membrane potential produced as two or more inputs, occurring at different times but from the same neuron
are added together.
C) When two action potentials arriving from two neurons are added together
D) When two action potentials arriving in short succession from the same neurons are added together
E) none of the above ANS A)Membrane potential produced as two or more inputs, from two or more
neuron are added together.
7) The absolute refractory period of an action potential
A) allows the next action potential to be fired but only when the stimulus is stronger
B) ensures one-way travel down an axon and prevents summation of action potentials.
C) only prevents summation of action potentials.
D) only ensures one -way travel down an axon. ANS B) ensures one-way travel down an axon and
prevents summation of action potentials.
8) Choose which items that are correctly matched. Note that the text refers to the voltage gate as the 'activation
gate'.
A) voltage gate closed during depolarization
B) inactivation gate closed during repolarization
C) inactivation gate open during repolarization
D) voltage gate open at rest
E) All of the answers are incorrectly matched. ANS B) inactivation gate closed during repolarization
9) Autonomic motor neurons are subdivided into the
A) central and peripheral divisions.
