BIO 201 NERVOUS SYSTEM TEST PRACTICE

Most neurons in the CNS communicate with _____ to _____ other neurons.

100s, 1000s

The brain and spinal cord comprise the _____ nervous system. All nerves of the body residing outside of the brain and spinal cord comprise the _____ nervous system.

CNS, peripheral

Small, variable intensity, transient changes in membrane potential that moves the potential closer to threshold are referred to as _____ post-synaptic potentials or "____".

EPSP

_____ is a common inhibitory neurotransmitter in the CNS.

GABA

Small variable intensity, transient changes in membrane potential that moves the potential further away from threshold are referred to as _____ post-synaptic potentials or "____".

IPSP

A neuronal impulse is also referred to as an _____, which indicates that it is a "moving" region of "voltage change" that migrates along the neuronal cell membrane.

action potential

Sensory neurons are also referred to as _____ neurons while _____ neurons carry motor impulses. The most common type of neuron is the _____ which communicates from one neuron to another

afferent, efferent, interneuron

Long extensions off neuronal cell bodies that conduct impulses away from the cell are _____

axons

At the axon terminals, voltage-gated _____ channels open in response to the arriving action potential. This triggers _____ vesicles to release _____ into the _____.

calcium Ca+, synaptic, neurotransmitters, synaptic cleft

In general, positively charged ions are termed _____

cations

The small extensions off of the neuronal cell bodies that receive stimuli are _____.

dendrites

Overall, two important factors drive the movement of Na+ and K+ across the membranes. These are the _____ gradient and the _____ gradient.

electrochemical, concentration

_____ are specialized epithelial cells in the CNS that produce _____

ependymal cells, cerebrospinal fluid

_____ of Na+ causes _____ of the membrane, which is the first phase of the action potential.

influx, depolarization

Action potentials travel fastest in axons that are _____ and _____. The fastest neuronal axon fibers are A-type fibers. These carry _____ and _____ motor signals. The slowest fibers are the C-type fibers. These fibers are _____ and _____ so they transmit action potentials much slower than A-type fibers.

large diameter, myelinated, pain, voluntary, small diameter, unmyelinated

The two ways ions may pass across a membrane involve using _____ channels and _____ channels.

leakage, gated

Movement of Cl- into a neuronal cell would make a neuron _____ likely to fire an action potential.

less

_____ is a CNS disease where the _____ of motor neurons is degenerating or being destroyed, which interferes with neuronal impulses. This is a progressive disease that causes widespread motor deficits.

multiple sclerosis, myelin sheath

An "excitable" cell is one that can quickly and dramatically change its resting membrane potential. Two types of examples of excitable cells include _____ and _____ cells.

muscle fibers, neuronal

On the inner cell membrane surface of a resting neuron, there is an accumulation of _____ charge.

negative (anionic)

The cells that support, nourish and protect neurons are the _____

neuroglial cells

The dark granular substance inside neuronal cell bodies are called _____. It is composed of dense collections of _____ where _____ occurs

nissl substance, ribosomes, protein synthesis

_____ is an example of a drug that block the opening of Na+ channels, thus blocking the initiation of neuronal action potentials.

novocaine

_____ are cells that electrically insulate neuronal axons in the central nervous system. This electrical insulation is referred to as _____

oligodendrocytes, myelin

When _____ charged ions flow into a neuron, the resting membrane potential becomes less negative.

positive (cationic)

Neurotransmitters bind to specific _____ on the neuronal cell surface. This binding triggers the opening of ion channels that temporarily change the nearby membrane potential. These small, variable, transient changes in membrane potential are referred to as _____ potentials.

receptors, graded

The _____ period of an action potential causes that region of membrane be temporarily unresponsive to another stimulus. This ensures that action potentials migrate in one direction, namely, away from the _____.

refractory, soma

There is a greater concentration of _____ions accumulating on the outer surface of resting neuronal membranes than on the inner surface.

sodium

Voltage-gated _____ channels are triggered to open when the resting membrane potential reaches about _____which is referred to as the _____ potential.

sodium, -55MV, threshold

The Na/K pump operates by transporting three _____ ions out of the cell while transporting two _____ ions into the cell

sodium, potassium

The cell body of a neuron is the _____

soma

The branch of the autonomic nervous system that induces the "flight or fight" response is the_____

sympathetic

_____-gated ion channels open or close only in response to a change in the nearby membrane potential.

voltage

When enough excitatory stimuli act on a neuronal cell, _____-gated Na+ channels on the axon _____ (or "trigger zone") open. Opening of these channels results in the movement of Na+ _____ the cell which causes the inside charge to become more _____.

voltage, hillock, into, positive

For any given neuron, all action potentials are of the same intensity. This is referred to as the "_____" principle. In order to alter the intensity of a given neuronal stimulus, the _____ of firing of action potentials is increased.

"all or none", rate

In electrical terms, "potential" is synonymous with "_____"

"voltage"

The second phase of the action potential ends when the membrane potential reaches about _____ which triggers the inactivation of the _____ channels

-50MV, K+

The typical neuronal resting membrane potential measures approximately _____

-70MV

After the first phase of the action potential, the _____ channels becomes inactivated while the _____ channels begin to open. This occurs when the membrane potential reaches approximately _____. The opening of these channels results in the _____ movement of _____. This second phase of the action potential is the _____ phase.

NA+, potassium, +30MV, outward, K+, repolarization