Dendrites and cell bodies are capable of producing action potentials.

True  
*False  

Additional stimulation beyond the threshold of excitation will result in a greater depolarization of the membrane during an action potential.

True  
*False  

The sodium-potassium pump is what normally brings the membrane back to its original state of polarization after the peak of the action potential.

True  
*False  

Increasing the electrical gradient for potassium would reduce the tendency for potassium ions to exit the neuron.

*True  
False  

At rest, the inside of a neuron's membrane is more negative than the outside.

*True  
False  

One disadvantage of the blood-brain barrier is that it keeps out most forms of nutrition.

*True  
False  

Oligodendrocytes in the periphery are specialized types of glia.

True  
*False  

Glia serve many functions.

*True  
False  

An afferent axon brings information into a structure.

*True  
False  

Neurons receive information and transmit it to other cells.

*True  
False  

Why are local neurons more difficult to study?

        *a.    They are so small.
        b.    They die if separated from other neurons.
        c.    They exist only in humans, so there are ethical considerations.
        d.    There are so few of them, they are difficult to find.

What are the nodes of Ranvier?

        a.    Gates in the membrane that admit all ions freely.
        b.    Places where dendrites join the cell body.
        *c.    Gaps in the myelin sheath.
        d.    Branching points in an axon.

What will affect the speed of an action potential?

        a.    The time since the last action potential.
        b.    The strength of the stimulus.
        c.    The length of the axon.
        *d.    The resistance of the membrane.

The presence of an all-or-none law suggests that neurons can only convey different messages by changing their:

        a.    sodium-potassium pump activity.
        b.    size of action potentials.
        c.    speed of action potentials.
        *d.    rate or pattern of action potentials.

At the peak of the action potential, the electrical gradient of potassium:

        a.    pulls potassium into the cell.
        b.    is the same as during the resting potential.
        *c.    pushes potassium out of the cell.
        d.    pulls sodium into the cell.

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their:

        a.    length.
        b.    threshold.
        *c.    permeability.
        d.    number.

If depolarization is less than the cell's threshold:

        *a.    sodium crosses the membrane only slightly more than usual.
        b.    potassium is prevented from crossing the membrane.
        c.    sodium is prevented from crossing the membrane.
        d.    the cell will still produce an action potential.

Stimulus A depolarizes a neuron just barely above the threshold. Stimulus B depolarizes a neuron to 10 mV beyond threshold. What can we expect to happen?

        a.    Stimulus B will produce an action potential that is conducted at a faster speed than A.
        b.    Stimulus B will produce an action potential of greater magnitude than stimulus A.
        *c.    Stimulus A and stimulus B will produce the same response in the neurons.
        d.    Stimulus B will produce an action potential but stimulus A will not.

What is one major cause for the resting potential of a neuron's membrane?

        *a.    The sodium-potassium pump.
        b.    The refractory period of the membrane.
        c.    A difference in size between axons and dendrites.
        d.    A high permeability of the membrane to water molecules.

The sodium-potassium pump, repeatedly transports three ________ ions out of the cell while drawing two ________ ions into it.

        a.    potassium; calcium
        b.    potassium; sodium
        c.    calcium; potassium
        *d.    sodium; potassium