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Absolute and relative refractory periods are important aspects of which of the following? a Action potentials b Resting potentials c Hyperpolarizing graded potentials d Graded potentials

a Action potentials

Which term describes the cell membrane potential of a neuron at rest? a polarized b hyperpolarized c depolarized d repolarized

a polarized

Saltatory conduction refers to which of the following? a The conduction of a graded potential along a myelinated axon. b The conduction of an action potential along a myelinated axon. c The conduction of an action potential along an unmyelinated axon. d The conduction of a graded potential along an unmyelinated axon.

b The conduction of an action potential along a myelinated axon.

In the process of generating an action potential, which occurs first? a voltage-gated K channels open b ligand-gated Na channels open c voltage-gated Nachannels open d voltage-gated Na channels close

b ligand-gated Na channels open

Identify the channels most directly responsible for the voltage change recorded in PHASE 1 of the graph. a ligand-gated Na channels b voltage-gated Na channels c ligand-gated K channels d voltage-gated K channels e K leak channels

b voltage-gated Na channels

What is the primary difference between graded potentials versus actions potentials? a Action potentials occur in all cells, while graded potentials occur only occur in neurons and muscle cells b In neurons, graded potentials occur in axons, while action potentials occur in the dendrites and cell bodies c In neurons, action potentials occur in axons, while graded potentials occur in the dendrites and cell bodies d Graded potentials do not involve movement of ions across the membrane, while action potentials do involve the flow of ions across the neuron membrane

c In neurons, action potentials occur in axons, while graded potentials occur in the dendrites and cell bodies

Which of the following is primarily responsible for ESTABLISHING the RESTING membrane potential of a cell? a gated Na and K channels b faster leaking (greater permeability) to Na c faster leaking (greater permeability) to K d all of the above

c faster leaking (greater permeability) to K

As the axon hillock depolarizes, voltage-gated Na+ channels open and Na+ moves (into or out of) ______________ the cell causing further (depolarization or repolarization) ______________. a out of; depolarization b into; repolarization c into; depolarization d out of; repolarization

c into; depolarization

During the relative refractory period, a second action potential a cannot be elicited b can be elicited by a threshold stimulus c can be elicited by a subthreshold stimulus d can be elicited by a suprathreshold stimulus e Either B or D

e Either B or D

Hypokalemia (low extracellular K+ concentration), if sustained, will cause a depolarization b hyperpolarization c maintenance of resting membrane potential d difficulty achieving action potentials e both B and D are true

e both B and D are true

Identify the type of channel most likely to be open during the repolarization phase of the following graph. a ligand-gated Na+ channels b voltage-gated Na+ channels c K+ leak channels d Na+ channels e voltage-gated K+ channels

e voltage-gated K+ channels

A graded potential may be depolarizing or hyperpolarizing.

true

A strong stimulus produces a strong action potential.

false