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Presenter: Romario Dixon
Types of Nervous Tissue
 Nervous tissue consists of two main types of cells:
neurons and neuroglia.
 Nerve cells, or neurones(also written "neurons")
transmit nerve impulses that move information
around the body.
Neuroglia are also known simply as "glia" and have
various functions in support of nerve cells but do not
transmit nerve impulses themselves. More
information about both of these types of cells follows
Neurons
 Neurones (nerve cells) are sensitive to various types of
stimuli such as heat/cold, light/dark, pressure.
They transmit electrical nerve impulses thereby
moving information around the body.
The structure of a neurone
Neuroglia / Glia
 Neuroglia are sometimes known as simply "Glia".
They are not sensitive to stimuli and so do not
generate or conduct nerve impulses. "Glia" or
"Neuroglia" are therefore sometimes referred to as the
"non-nervous cells of the nervous system".
Their functions within the nervous system depend on
the specific type of neuroglia
Types of Neuroglial Cell:
 Astroglial Cell
Astrocyte
Structure:
 An astrocyte is a star-shaped cell that has many processes extending
from its cell body into the surrounding network of nerve fibres.
Function(s):
 Supply of nutrients to neurons.
 Removes excess neurotransmitters
 Maintains appropriate balance of Ca2+ and K+ ions (which are
important in passing nerve impulses at synapses).
 Helps migration of neurons during brain development.
 Aids formation of the blood-brain barrier.
 (Possibly participating in information storage processes)
Ependymal Cell
 Ependymal cells are found in the Central Nervous
System (CNS),
that is in the tissues of the Brain and Spinal Cord.
Function(s):
 Protection: Forms lining of the ventricles of the brain and
central canal of the spinal cord.
 Forms cerebrospinal fluid (CSF).
 Aids circulation of cerebrospinal fluid (CSF).
 Ependymal cells form the extremely thin membrane called
the ependyma that lines the ventricles of the brain and
choroid plexuses
Ependymal Cell Structure:
Microglial Cell
 Microglial cells are sometimes known simply as "microglia"
and are found in the Central Nervous System (CNS), that is
in the tissues of the Brain and Spinal Cord.
Structure:
Microglia are small glial cells.
Function(s):
 Protects CNS neurons from disease e.g. by clearing away debris and dead cells. Therefore some texts
describe microglia has having a "mainly scavenging" function.
 Microglia may be compared with macrophages (which are large
scavenger cells, not specific to the nervous system).
A video of the structure and
function of nerve cells
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