Transcript chp_16-nerves

Nerves
Nerves
NEUROGLIA are the cells that
insulate, support, and protect the
NEURONS.
There are 3 different kinds of
neurons:
Afferent neurons-sensory
Efferent neurons-motor
Interneurons-associative neurons
Nerves
► There
are 3 different kinds
of neurons:
 Afferent neurons-sensory
 Efferent neurons-motor
 Interneurons-associative
neurons
Nerves
Afferent Neurons-emerge from skin
and carry message to spinal cord
and brain.
Nerves
► Efferent
neurons-carry message from
brain and spinal cord to muscle
► Interneurons-carry
impulses from the
sensory neuron to
the motor neuron
Nerves
► Function
of Nerves:
 The inside of a neuron is more negative than
the outside.
Nerves
Function of Nerves:
►

When the neuron is
stimulated the ions
move across the
membrane, inside is
more positive,
outside negative.
This creates an
action potential.
Nerves
Membrane excitability- ability of
nerves to carry impulses by creating
electrical charges, this happens
when in state of action potential.
Nerves
The axon sends the message to the
dendrite, in between is a synaptic
cleft.
Nerves
► The
nerve message
goes from a one cell
to the next, this is
called a synapse.
Nerves
Nerve injuries are caused by:
-trauma
-compression
-traction
Nerves
► Nerve
fibers are
inside an
insulation called
a myelin sheath
Myelination
The myelin sheath helps action potentials travel
faster through the nervous system.
Nerves
► If
the myelin sheath
stays intact, but the
nerve fiber is damaged,
the fibers can grow
inside the myelin
sheath
Nerves
►If
both are not intact, a neuroma
will develop at the end farthest from
the brain
Nerves
Neuroma-a nerve scar, may be
painful and cause electrical feeling
when touched.
If the myelin sheath can be repaired,
the nerve fibers will grow back.
They return at approx. 1 inch every
month.