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Nervous Tissue - Fill in the blanks:
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.
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.
The branch of the autonomic nervous system that induces the "flight
or fight" response is the_____.
The cells that support, nourish and protect neurons are the _____.
The cell body of a neuron is the _____.
Long extensions off neuronal cell bodies that conduct impulses away from
the cell are _____.
The dark granular substance inside neuronal cell bodies are called _____.
It is composed of dense collections of _____ where _____ occurs.
_____ are cells that electrically insulate neuronal axons in the central
nervous system. This electrical insulation is referred to as _____.
_____ 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.
_____ are specialized epithelial cells in the CNS that produce _____.
In general, positively charged ions are termed _____.
On the inner cell membrane surface of a resting neuron, there is an accumulation
of _____ charge.
In electrical terms, "potential" is synonymous with "_____".
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.
The typical neuronal resting membrane potential measures approximately
_____.
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.
There is a greater concentration of _____ions accumulating on the outer
surface of resting neuronal membranes than on the inner surface.
The two ways ions may pass across a membrane involve using _____ channels
and _____ channels.
The Na/K pump operates by transporting three _____ ions out of the cell
while transporting two _____ ions into the cell.
_____-gated ion channels open or close only in response to a change in
the nearby membrane potential.
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.
When _____ charged ions flow into a neuron, the resting membrane potential
becomes less negative.
Voltage-gated _____ channels are triggered to open when the resting membrane
potential reaches about _____which is referred to as the _____ potential.
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 _____.
_____ of Na+ causes _____ of the membrane, which is the first phase of
the action potential.
_____ is an example of a drug that block the opening of Na+ channels, thus
blocking the initiation of neuronal action potentials.
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.
The second phase of the action potential ends when the membrane potential
reaches about _____ which triggers the inactivation of the _____ channels.
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 _____.
Overall, two important factors drive the movement of Na+ and K+ across
the membranes. These are the _____ gradient and the _____ gradient.
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.
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.
At the axon terminals, voltage-gated _____ channels open in response to
the arriving action potential. This triggers _____ vesicles to release
_____ into the _____.
Most neurons in the CNS communicate with _____ to _____ other neurons.
The small extensions off of the neuronal cell bodies that receive stimuli
are _____.
Small, variable intensity, transient changes in membrane potential that
moves the potential closer to threshold are referred to as _____ post-synaptic
potentials or "____".
Small variable intensity, transient changes in membrane potential that
moves the potential further away from threshold are referred to as _____
post-synaptic potentials or "____".
_____ is a common inhibitory neurotransmitter in the CNS.
Movement of Cl- into a neuronal cell would make a neuron _____ likely to
fire an action potential.
Answers:
The brain and spinal cord comprise the central nervous system. All nerves of the body residing outside of the brain and spinal cord comprise the peripheral nervous system.