Ch. 12 Anatomy

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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?


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