Neuroglia Protect Neurons
and Help Them Do Their Jobs
Oligodendrocytes produce and maintain myelin.
Ependymal cells produce cerebrospinal fluid (CSF).
As mentioned previously, neuroglia, or glial
cells, provide various support functions for
Neuroglia are found in both the CNS and
PNS:
CNS neuroglia (
Figure 7.4
) include the fol-
lowing:
Microglia
provide
protection
against
microbial organisms.
Astrocytes
form the
blood-brain barrier
to
protect neurons from harmful chemicals.
(GLË-al)
neurons.
PNS neuroglia include the following:
blood-brain
barrier
A barrier
consisting of special-
ized brain capillaries
and astrocytes that
prevents the passage
of materials from the
blood to the cerebro-
spinal fluid and brain.
Schwann cells produce myelin around a
single axon and help in neuron regeneration
(see Figure 7.3).
Satellite
(SAT-i-lit)
cells
support
cells
within
the
ganglia
that
regulate
the
exchange of material between the neurons
and the surrounding interstitial fluid.
Now that we have looked at the cells that com-
prise the nervous system, let’s see how they
communicate with each other.
N euroglia • Figure 7.4
Neuroglia provide many support-
ing functions that assist neurons in
both the CNS and PNS.
Cells of
pia mater
(covering around brain)
Microglia
(mi-KROG-le-a'
protect CNS cells
by engulfing
invading cells
through
phagocytosis.
Neuron
Blood capillary
Microvillus
Cilia
Astrocytes
(AS-tro-sfts)
• Support neurons
• Protect them from harmful
substances
• Maintain proper chemical
environment for generating
nerve impulses
• Play a role in
learning/memory
• Help form blood-brain barrier
• Assist with growth/migration
of neurons during
development
Node of Ranvier
Myelin sheath
Axon
Oligodendrocyte
(ol'-i-go-DEN-dro-sft) produces
and maintains myelin around
axons of several CNS neurons.
&
"
i r
U:
Neurons
Ependymal cells
(e-PEN-de-mal)
line ventricles of the brain and
central canal of the spinal cord.
They produce cerebrospinal fluid
(CSF) and assist in its circulation.
Ventricle (space) of brain
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