1. DO NOW WEDNESDAY
Explain how you think the brain sends and receives messages to and from the body.

2. PLAN
To describe the structure and function of a sensory/motor neuron.
To gather and synthesize information that sensory neurons respond to stimuli by sending messages to the brain for an immediate response or for storage as memory. DO
PowerPoint Notes over Neurons
Color and complete neuron picture

3. Neurons (Nerve Cells)

4. Characteristics of Neurons
Are nerve cells
Are the longest cells in the body
Function like the wires in electronics
Carry messages from the brain to the body or the body to the brain

5. Structure of a Neuron

6. Types of Neurons There are two type of neurons:
A. Sensory: allow you to sense your environment;
carry messages from your body to your brain;
connect your brain to your five senses (eyes, ears, skin, tongue, nose)
B. Motor: allow you to respond to your environment;
carry messages from your brain to your body
connect your brain to your muscles to allow movement

7. Function of Neuron Parts
Dendrites: receive the chemical signal (neurotransmitter) from the adjacent nerve cell
Cell body: produces the energy and protein that builds and maintains the nerve cell
Nucleus: control center of the nerve cell, direct its function
Axon: the “wire” of the nerve signal; conducts the electrical impulse
Myelin sheath: the fatty insulation that keeps the electrical signal on the axon
Axon terminals: send the chemical signal (neurotransmitter) to the next nerve cell or another cell such as a muscle cell

8. How does a Neuron send a signal?
Chemical
Signal
Chemical
signal
Electrical
Signal


9. How does a Neuron send a signal?
Neurotransmitter
chemical signal 
dendrites
axon

electricity
Axon
terminals

10. How does a Neuron send a signal?
Dendrites receive neurotransmitter from adjacent neuron.
Neurotransmitter generates electrical signal in neuron.
Electrical signal travels down axon and axon terminals.
Neurotransmitter is released by axon terminals.
Neurotransmitter travels across synapse and is received by dendrites of next nerve cell.
Steps 1-5 are repeated over and over as message is sent from brain to body (by way of motor neurons) or body to brain (by way of sensory neurons).
NOTE: The receiving cell of the neurotransmitter
can be a muscle cell if the sending cell is a motor
neuron.

11. What happens then?
Once the message reaches its destination, what happens depends upon the destination.
If the destination was the brain, then the brain will process the information and send a response message out to a part of the body or may store the information for future use (memory and learning).
If the destination was a body part, then that body part will do what was instructed by the brain.

12. Label A Neuron
Use this website to help you label your picture of a neuron

13. DO NOW WEDNESDAY
Describe how neurons send messages throughout your body.