1. Neurons: The Building Blocks of the Nervous System.
Essential Question: How are neurons structured and how do they send and receive information within the nervous system?

2. Part I: The Structure of Neurons

3. A. What is a Neuron???
A Neuron is a cell that has been specifically designed to receive, transit, and interpret information by sending and receiving electrical impulses.
These neurons communicate with each other throughout the nervous system.
Your nervous system is made up of hundreds of billions of neurons that must work together for you to maintain proper mental health.
-Unlike most other cells, neurons cannot reproduce, so if they die, you lose them forever.

4. Dendrites of another neuron
B. Parts of the Neuron
Cell Body
Dendrites
Axon
Myelin Sheath
Dendrites of another neuron
Axon of another neuron

5. 1. Cell Body Contains the nucleus
Contains the genetic information within the cell
Commands the rest of the cell in what to do, when and how to do it

6. 2. Dendrites The bushy, branching parts of the neuron
Their job is to receive impulses (messages) from other neurons and pass the information on to the cell body

7. 3. Axon The extension of the nerve cell
It ends in the terminal buttons
At these terminal buttons, the impulse either ends or is passed on to the next neuron

8. 4. Myelin Sheath This is primarily a protective structure
It insulates the axon and allows the electrical impulses to pass down the axon without the information being lost

9. C. Glial Cells: The Neurons’ Wingmen
Glial Cells are supporting cells for your neurons
-Literally provide structural support and nutrients to the neuron
They cover the neurons in a myelin sheath to protect them
They also clear debris from building up in the neuron
An Astrocyte connecting a capillary and a nerve:

10. Neuron Experiment: Congratulations, we are all now neurons
We must create a chain that allows us to pass information from one neuron to the next neuron
We will start simple and become more complex
We will try to pass one piece of information first and then progressively get more difficult
The shortest person will start and the tallest person will finish
SUMMARY: HOW DOES OUR EXPERIMENT MIMIC WHAT IS ACTUALLY OCCURING WITHIN THE NERVOUS SYSTEM?

11. Part II: How Neurons Function

12. A. Primary Role of Neurons
A neuron’s main role in the body is to collect, interpret, and pass on impulses throughout the Nervous System
This is a vastly important role, however, because our nervous system controls every other system in the body
This is, however, a vastly complicated series of events that requires constant adjustments and clockwork precicion

13. B. Neurotransmitters: The Messages
The information that is passed through the nervous system is contained in neurotransmitter
These neurotransmitters contain small pieces of chemical information that is specifically designed for delivery to a certain part of the system
There are many types of neurotransmitters with specific roles in the nervous system

15. C. Action Potential:
When dendrites stimulated, the delicate balance is altered
Positively charged ions rush down the axon
Causes release of chemicals from terminal buttons across the synapse into the next neuron

16. D. Power of the Myelin Sheath:
The myelin sheath insulates the axon
It also controls the amount of action potential within the axon
Generally speaking, the thicker the myelin sheath, the faster the impulse travels

17. E. Across the Synapse:
Once the action potential has been realized, the terminal buttons release the neural transmitters to the next cell
They must cross the synapse to the dendrites of the next neuron
If they fail to release the information, the command is stopped within that neuron

18. F. The end of the Impulse:
At some point, the impulse will end within one neuron
The reality is, however, that an alternate impulse now is sent back to the brain in the case of the sensory nerves

19. Sensory (Afferent) vs. Motor (Efferent)
sensory (afferent) nerve
CNS
e.g., skin
Neurons that send signals from the senses, skin, muscles, and internal organs to the CNS
motor (efferent) nerve
CNS
e.g., muscle
Neurons that transmit commands from the CNS to the muscles, glands, and organs
Gray’s Anatomy