Nervous Tissue
Li DongMei

Central nervous system (CNS)

Peripheral nervous system (PNS)
Composition of nerve tissue

Two types of cells
---Components:
 nerve cell: neuron
 Glial cell: neuroglial
---Function:
 Neurons : receive the stimulation, conduct
the nerve impulse
 Glial cell: support, protect and insulate,
nourish neurons
1. Neuron
1. Neuron
It is the structural and functional unit
of the nervous tissue.
 Neuron is a cell that transmits nerve
impulses
 10 billion neurons and more glial cells
form human nervous system
 Neuron consists of cell body(soma),
dendrite and axon.

Cell body
Dendrite
processes
Axon
① Cell body of neuron (perikaryon)
①
② Dendrites
No Golgi complex, other contents
are similar to the cell body.
Increase the receptor surface area
of a neuron.
To receive stimuli from other
neurons or from the external
environment.
③ Axon



A Long Fiber that carries
impulses away from the
cell body.
Each neuron has only
one axon.
The Axon Ends in a
series of small swellings
called axon terminals
2. Synapses
2. Synapses

Specialized junctions between neurons,
between axons and effector cells
Classification
Electrical synapses
gap junctions
Chemical synapses
taking neurotransmitter as
communicating medium
Chemical
synapse
Synaptic transmission





Calcium gates open
Synaptic vesicles release neurotransmitter
Neurotransmitter binds with postsynaptic
receptors
The postsynaptic membrane is excited or
inhibited
The neurotransmitter is degraded and recycled.
3. Glial cell(neuroglia)
3. Glial cell(neuroglia)
3. Glial cell(neuroglia)
Schwann cell
envelop the axon end to end to form
myelin-sheath in PNS and
Satellite cell (capsular cell)
one layer of flattened or cuboidal cell,
with round, ovoid and dark N
surrounding the Neuron in ganglion
4.Nerve fiber and Nerve
Nerve fiber
definition: axon enveloped by neuroglial
cells
classification: according to myelin-sheath
 myelinated nerve fiber
 unmyelinated nerve fiber
myelinated nerve fiber in CNS
---structure:
 similar to in PNS
 myelin-sheath
formed by flattened
ending of oligodendrocyte’s processes
 one oligodendrocyte can envelop many
axons
 no incisure and basement membrane

Nerve
5. Nerve Ending