Neuron
Structure and
Function
Nervous System
 Nervous
system is
composed of specialized
cells called neurons.
 Neurons have long
“arms” called axons and
dendrites.


Axons carry impulses
away from cell body.
Dendrites carry impulses
to the cell body
 Connections
between axons and dendrites forms
our intelligence.
Central Nervous system
contains the brain &
spinal cord.
Cell bodies, axons, & dendrites in the
human brain.
Peripheral Nervous system (PNS)
 contains
all nerves
leading to and from
the Central Nervous
System
 Sensory receptors:
Nerves that carry
impulses towards
CNS

Detect light, pressure and
heat.
Pair share: Why do you think it
is called the “peripheral”
nervous system?
Motor neurons
 Nerves
that carry impulses from the CNS to
muscles or glands.
 Impulses
are
referred to as
action potentials.
 Dendrites
receive
action potentials
from other
neurons.
 Axons carry
action potentials
to other neurons.
 Dendrites take
action potential
to cell body,
axons away from
cell body.
Pair share: How many directions
can a signal travel in an nerve cell?
Neuron
Structure
Axons
Cell bodies of neurons
myelin sheath
 Serves
to insulate axons &
dendrites and therefore
speed up the action
potential.
 The
myelin sheath is
made up of Schwann
cells.
Nodes of Ranvier
The
gaps between Schwann cells are
called the Nodes of Ranvier.
The action potential jumps from
Node of Ranvier to Node of Ranvier.
White board review
1.
2.
3.
What are the 2
components of the
central nervous
system?
What 2 types of
nerves make up the
PNS?
What do Axons do?