Basic structure of neurons

1. The Nervous System:
Structure of Neurons
Ch 33.1
Mrs. Neistadt

2. Neurons: An overview

3. Neurons
• *Neurons are special cells that send
messages through the nervous system.

4. Neurons
• *There are five main parts of a neuron:
1.Cell body
2.Nucleus
3.Dendrites
4.Axon
5.Myelin Sheath

5. Parts of Neuron
• *Dendrites- receive
signals from other
neurons and send the
signal to the cell
• *Cell body- holds the
nucleus and other
organelles of the cell
• *Axon- carries the
nerve impulse from the
cell to other neurons
and muscles

6. Parts of Neuron
• *Nucleus- Contains the DNA and controls
the cell activities
• *Myelin Sheath – wraps around the axon
of some cells to cause the nerve impulse
to move faster

7. Nerve Impulse
• *A nerve impulse is when a neuron sends
a signal to another neuron.
• *There are three types of neurons:
– *Sensory Neurons send impulses from the
skin to the brain and spinal cord
– *Motor Neurons carry signals from the brain to
the muscles
– *Interneurons carry nerves impulses to motor
neurons or to the spinal cord and brain

8. Action Potential
• *Another name for nerve impulse
is an Action Potential.
• The speed of an action potential changes.
• *If the axon has a myelin sheath, the
speed of the impulse is much faster.
• *Neurons with myelin carry impulses of
sharp pain
• *Neurons without myelin carry impulses
that cause dull, throbbing pain.

9. Synapse

10. Synapse
• *Synapse- a small gap between the axon
of one neuron and the dendrite of another
neuron.
• *A neurotransmitter is a chemical signal
sent from one neuron to another.

11. Your Turn…
• Create a neuron using pipe cleaners
• Attach your neuron to your classmates’
creating a web of neurons.
• You must have:
– Cell body
– Dendrites
– Axon
– Myelin sheath