Neuron - Structure and Function

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Objective

SWBAT to explain relationship between structure and function of neuron.

Big Idea

Students explore structure and function of neuron.

Engage

5 minutes

To hook students I show students a video (below) that introduces them to both the structure and function of a neuron.

Students answer the following questions as they watch the video:

1)  Everything we do, feel, or think is the result of what basic units of brain structure? (MS-LS1-3 - body is a system of interacting subsystems composed of groups of cells.) 

2)  How many neurons are contained in the human brain?

3)  How are neurons similar to a colony of ants?

4)  The power of neurons is the result of its connections to other neurons.  Why do you think this is?

5)  How does a neuron "turn on or off" a neighboring neuron?

6)  Neuron firings represent __________________, _________________, ________________.

7)  Do scientists know everything there is to know about neurons?  If not, what is one thing that scientists are still trying to find answers to?

 

Explore

20 minutes

Now students explore the structure of a neuron by creating a model using pipe cleaners. (SP2 - Developing and Using Models - Develop a model to describe unobservable mechanisms/MS-LS1-2. Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.)  

Directions for Neuron Model:

Materials:

1)  Piper Cleaners (5 different colors: one color each for the dendrites, cell body (soma), axon, myelin sheath and synaptic (axon) terminal)

1. Take one pipe cleaner and roll it into a ball. This will be the cell body.

2.Take another pipe cleaner and attach it to the new "cell body" by pushing it through the ball so there are two halves sticking out. Take the two halves and twist them together into a single extension. This will be the axon.

3.Take other pipe cleaners and push them through the "cell body" on the side opposite the axon. These are dendrites. These can be shorter than your axon and you can twist more pipe cleaners to make more dendrites.
4.Wrap small individual pipe cleaners along the length of the axon. These will represent the myelin sheath.

5. Wrap another pipe cleaner on the end of the axon. This will be the synaptic terminal.

Teacher Note:  I have students label and write the function of each part of neuron in the next section of lesson.

Explain

10 minutes

In this section of the lesson students watch a video from Khan Academy which explains the function of the dendrites, cell body, axon, myelin sheath and synaptic (axon) terminal.

As students watch this video, they are required to to label their model and include a brief description of each part's individual function.


An example is shown below:


In addition to the labeling of their model, I have students answer the following questions:

1)  In the start of video, the presenter makes a claim that the neuron should be considered in the top two of most interesting cells. What evidence does he use to support his claim?

2)  What is the essential function of the neuron?

3)  Are all axons of the same length? Please explain your answer using evidence from video.

4)  What is found at the end of the axon?  Why do you think it's given this name?

5)  What cells make up the myelin sheath? Please label these cells in your neuron model.

6)  What is the name of the spaces between the myelin sheath?  What's the reason behind that name?

7)  What is the direction of message transmission in a single neuron? dendrite -> axon/synaptic terminal or axon/synaptic terminal ->axon.

Elaborate

20 minutes

We're learning a lot of new words, and attaching those to images, so I use a quick class discussion about what they learned from watching the Khan Academy video to help aid in transfer. I particularly emphasize the location and function of dendrites, cell body (soma), axon, myelin sheath, and synaptic terminal.   

In addition I clear up some confusion that might arise by pointing out that the both the soma/cell body and axon/synaptic terminal are analogous to one another.

I then transition discussion to the relationship between structure and function of a neuron.

(CCC - Structure and Function - Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function.) 

I ask students:

  • "How does that long, thin shape help it do its job quickly?" An analogy that has worked well with my students is to make a comparison with telephone wires."

  • "What do we use in everyday life to communicate with people across town or across the country?" (Telephone) People (and, increasingly, computers) are able to communicate rapidly and clearly through the use of telephones.
  • "How is the signal sent?" Over a long, thin wire. This is a very efficient shape for message transmission - in the outside world and in our bodies.

 

In the last part of this section of lesson, students read and complete the questions from the article Hard Hit (type in search box) from ReadWorks*. This article deals with the harmful effects of concussions, in this case football players, on neurons.

The objective of this reading is to bring a real life application to todays lesson. In addition students are given practice in answering text-dependent questions.

*You need to set up an account to use this great free resource. 

Evaluate

5 minutes

We covered a lot of ground today, and I'm checking on student comprehension using an Exit Slip. The slip covers the following:

  • The structure and function of the neuron.
  • Consequences of neuron damage.  Students must cite evidence from the article.  (RST.7.1 - Cite specific textual evidence to support analysis of science and technical texts.) 
  • The relationship between the structure and the function of neuron. (CCC - Structure and Function/MS-LS1-2. Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.)