Ch. 12 Anatomy
the all-or-none law
"An action potential either happens or it doesn't." This statement could also be called ______.
afferent;toward
Sensory ______ neurons carry information ______ the central nervous system.
end bulbs/terminal boutons
Synaptic knobs are also called ______.
autonomic motor nervous system
The ______ is the functional division of the nervous system that controls the involuntary movement of smooth muscle.
central nervous system
The ______ is the structural division of the nervous system that contains the brain.
toxins
The blood-brain barrier helps protect the brain from ______.
ependymal cells
The choroid plexus is made from capillaries and ______.
the length of time channels are open
The duration of a graded potential is dependent on ______
areolar connective tissue
The endoneurium is made of ______.
an individual axon
The endoneurium surrounds ______.
cerebrospinal fluid
The ependymal cells help produce ______.
ependymal cells
The lining ventricles of the brain is a location of ______.
axon
The myelin sheath covers ______.
lipids
The myelin sheath is made of a high percentage of ______.
an increase
The nerve impulse causes ______ in the number of calcium ions that enter the synaptic knob.
astrocyte
The perivascular feet of the ______ help create a blood-brain barrier.
summation
The process by which postsynaptic potentials are added together at the initial segment is known as
resting membrane potential
The relative difference in charge across the plasma membrane of a resting neuron is known as the
millivolts
The resting membrane potential is measured in ______.
neurofibril nodes
The small spaces that interrupt the myelin sheath are called ______.
between
The synapse is located ______ the presynaptic neuron and postsynaptic neuron.
at the extreme tips of the axon
The synaptic knob is found ______.
neurilemma
The thin outer layer of the neurolemmocyte is called the ______.
4
There are ______ different types of glial cells in the CNS.
transmissive
Voltage-gated calcium channels are found mostly in the ______ segment of a typical neuron.
unipolar and bipolar
What are the two structural examples of sensory neurons?
positive
When sodium ions flow into a cell through a leak channel they make the membrane potential more
astrocytes
Which glial cell occupies the space of dying neurons?
spinal nerves only
Which nerves extend from the spinal cord?
spinal and cranial
Which terms are used for the structural classification of nerves?
interneurons
______ are also called association neurons.
voltage gated channels
______ are essential for the generation of an action potential.
neurons
______ are excitable cells that initiate and transmit electrical signals.
voltage gated ion channels
______ are not commonly found in the receptive segment of a neuron.
astrocytes
______ are star shaped.
multiple sclerosis
______ is caused by the destruction of oligodendrocytes.
neurolemmocyte
______ is the name of the glial cell in the peripheral nervous system that surrounds an axon.
microglia
______ represents the smallest percentage of CNS glial cells.
Oligodendrocytes
are large cells that ensheath many different axons.
presynaptic neuron
A ______ transmits an impulse through its axon toward the synapse.
some neurilemma remains
A damaged axon within the PNS can regenerate if ______.
axons
A fascicle is a bundle of ______.
perineurium
A fascicle is surrounded by a layer of dense irregular connective tissue called ______.
action potential
A flow of electrical current called a(n) _______ _______ is generated within the initial segment of a neuron.
diverging
A message traveling from one presynaptic neuron to multiple postsynaptic neurons is an example of a ______ circuit.
primary tumor
A tumor that originates within the organ that it is found is called a ______.
multipolar
All motor neurons are ______.
epineurium
An entire nerve is surrounded by a connective tissue covering called the ______.
an entire nerve
An epineurium surrounds ______.
chloride/potassium
An inhibitory neurotransmitter may cause the opening of a ______ channel.
axoplasm
Cytoplasm within an axon is called ______.
cilia
Ependymal cells produce and circulate cerebrospinal fluid. The ______ helps circulate the CSF.
peripheral
Guillain-Barré syndrome is a disorder of the ______ nervous system.
will not occur
If a subthreshold value is reached on an axon membrane, an action potential ______.
transmissive segment
In the ______ of a neuron, you would be likely to find voltage-gated calcium channels.
multipolar
Interneurons are ______ neurons.
sensory;motor
Interneurons facilitate communication between _______ neurons and ________ neurons
many
It usually takes ______ neurolemmocytes to myelinate one axon.
both Na+ and K+
Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______.
unipolar
Most afferent neurons are classified functionally as ______.
efferent
Motor neurons are classified as ______ neurons.
resting;potential
Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the ________ membrane ________.
ranvier
Neurofibril nodes are also called nodes of ______.
excitable cells that transmit electrical signals
Neurons are ______.
glial cells, meninges
Primary CNS tumors typically originate in tissues that can undergo mitosis like which of the following?