1. DNUR 3012 1
ANATOMY PHYSIOLOGY
IV
DNUR 3012
Prepared by: Miss Nadiah Shamsuddin
2. LEARNING OBJECTIVES
2
At the end of the learning session, students
will able to:
Describe the histological characteristic and the
functions of neurons and neuroglia.
Distinguish between gray matter and white
matter.
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6. NERVE CELLS (NEURON)
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Specific cells that transport electrical nerve
impulse.
Transport impulse from one part to others part of
body.
Property:
Electrical excitability (ability to produce action potential
and impulse in response stimuli).
Once they arise, action potentials propagate from one
point to the next along the plasma membrane due to the
presence of specific types of ion channels.
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8. Nerve Cells
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Nerve fiber is a general term for any neuronal
process (dendrite or axon)
The site of communication between two neurons
or between a neuron and an effectors cell is called
a synapse.
(Neuron synapse neuron)
Impulses transmit into neuron at synapse through
dendrite process and carry incoming impulse
towards cell bodies. Then transfer away from cell
body by axon.
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9. CELL BODY
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Contains:
Nucleus
Surrounded by cytoplasm that includes typical
organelles such as:
lysosomes, mitochondria and a Golgi complex
Nissl bodies (prominent cluster of rough
endoplasmic reticulum) :
sites of protein synthesis in neurons that was
used to replace cellular components, as a
material for growth of neurons and to regenerate
damaged axons in the PNS.
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10. Cell body
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Characteristics:
Different sizes with others
Protoplasma have granules
Neurons cells cannot divide like others cell body
Form grey matter in brain and spinal cord
Cells have one or more fibers (axons and
dendrite) will form white matter nervous system’s
organs .
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11. DENDRITE
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Dendrite’s shorter processes terminating mostly
near the nerve cell body. They touch the others
neuron at synapse.
Are conductive in nature :
receive and carry incoming impulses towards cell
bodies.
Have same structures like axons, but are usually
shorter and branching.
In motor neuron, they forms part of synapses.
In sensory neuron, they form the sensory
receptors that respond to specific stimuli.
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13. AXON
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Each neuron has one axon.
Axon may have branches along their length
known as axon collaterals.
Axon collaterals is divide into many fine
processes known as axon terminals.
Axon terminals:
Longer than dendrites , sometimes about 1
metre.
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15. AXON
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Has a long central core of cytoplasma called
axosplasma .
The cytoplasma is surrounded by plasma
membrane axolemma.
Together axoplasma with axolemma is called
as axis cylinder of the nerve fiber.
Axon:
the conducting region of the neuron.
It generates nerve impulses and transmit them
(typically away from the cell body.)
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16. AXON
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Insulated by myelin sheath
It gives white colour to the nerve fiber.
Has a series of Schwann cell plasma membrane
and also known as neurolemma.
There are tiny areas of exposed axolemma
between adjacent Schwann cells, called nodes of
Ranvier.
Nodes of Ranvier:
Assist in rapid transmission of nerve impulse.
(the speed of transmission of nerve impulse slower in
non-myelinated fibers.) DNUR 3012
18. Neurolemma
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A series of Schwann cell plasma membrane -
Thin membrane surrounding the myelin sheath
that found only around axons in the Peripheral
Nervous Sytem.
When the axon is injured, neurolemma assists
regenerations.
It forms a regeneration tube that guides and
stimulates growth of the axon.
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27. Nerve Impulse
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The electrical activity in the membrane of a
neuron.
Ways by which information is transmitted
within the nervous system along the axons of
the neurons.
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29. Types of neuron: Sensory or
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Afferent Nerves
Nerve that transmit impulse from peripheral body
through spinal cord to the brain to be interprets.
Example: from skin.
When action potentials are generated by sensory
receptors on the dendrites of these neurons, they
are transmitted to the spinal cord by the sensory
nerve fibers.
The impulse may then pass to the brain or to
connector neurons of reflex arcs in the spinal
cord.
Sensory receptors action potentials
dendrites sensory nerve fibers spinal cord
brain / connector neuron of spinal cord.
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30. Types of neuron: Sensory or
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Afferent Nerves
Sensory nerves from peripheral nerve are
non-myelinated and not have neurolemma.
From small division called as sensory nerve
ending.
Stimulation; pain, hot temperature impulse
transmit to sensory nerve brain
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32. Types of neuron: Motor or Efferent
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Nerves
Nerve that send impulse from brain to spinal
cord. Then it goes to skeletal muscle to
contract.
Brain spinal cord skeletal muscle
(contract).
The nearer motor nerve to muscle, it lost its
myelin sheath and neurolemma.
The nerve branches into filament and ends at
Motor End Plate.
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33. NEUROGLIA
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It is about half the volume of the Central
Nervous System (50%).
It held nervous tissue together.
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