Understanding the Structure of the Neuron!

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Objective

Students will develop and use models to identify the major anatomical components of the neuron.

Big Idea

Neurons are specialized cells with specific morphological features which allow them to generate and propagate electrical impulses over distances within the body.

Introduction

Lesson Background & Justification:

     A Neuron is a nerve cell that is the basic building block of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but are highly specialized to transmit information throughout the body in both chemical and electrical forms. There are also several different types of neurons responsible for different tasks in the human body. In this lesson, students investigate the structure of the neuron and learn to describe its morphological nature as it relates to its ability to regulate chemicals that transmit information within the brain and throughout the body. 

Lesson Preparations:

 In the effort to prepare for this lesson, I make certain that I have the following items in place: 

a) A class set of Neuron Slides: Carolina Biological Neuron Slides (1 per student pair)

b) A class set of Compound Light Microscopes (1 per student pair)

c) Student lab books.

Common Core and NGSS Standards:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

SP2- Developing and using models.

Standards Rationale:

      Modeling is the process by which scientists represent ideas about the natural world to each other, and then collaboratively make changes to these representations over time in response to new evidence and understandings. It is intimately connected to other scientific processes (asking questions, communicating information, etc.) and improves students ability to recall scientific jargon through association. In the classroom, it is important that teachers engage students in modeling practices, to set the foundation of success in a lesson or instructional unit. In this lesson modeling is used in concert with other science practices in the classroom to promote students’ reasoning and understanding of core science idea presented (structure and function of neurons). 

Engage

10 minutes

Section Sequence:

           In this section of the lesson, my goal is to draw students interest into the power of neural activity via its electrical properties. The idea is to empower students to inquire about why or how this actually happens and to prime them for the proceeding sections which explain how its structure makes it highly adaptable & replicable for the function(s) featured in the video clip below. This activity proceeds as follows:

a) Slide 1: In the effort to access students' preconceived ideas of energy generation & summation within the brain and the potential of transferring this energy to an external body using specific or specialized structures housed in the brain, ask: Is mind control of another individual possible? Explain. If so, what special features or smaller entities within the brain structure do you believe make this possible? Explain. Discuss students' ideas as a class. Give students an opportunity to illustrate their ideas on the board as well to share out (in lieu of or as a supplement to their verbal responses). 

Note: Responses generated from students in step a can be referenced in proceeding sections to credit and positively reinforce student input or to develop their initial concept of neuron form and function. 

b) Share with students that researchers have investigated the brains of primates to explore this phenomenon and that they will view a video clip to learn a little more about how they have accomplished this. 

       

b) Post video, discuss the contents of the video and focus on developing responses that relate similarities between the structure and function of brain cells to those computer systems and wires that connected the two organisms. 

Standards Covered:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

Explore

30 minutes

Section Sequence:

           In this section of the lesson, my goal is to provide students with an opportunity to examine the cells that make up the brain prior to a formal introduction of nerve cell structure and function. The idea is to encourage students to explore the structures of the neuron and imply functions from their observations. This activity proceeds as follows:

a) Slide 2: State: As we discussed, the brain possess structures that are highly adapted to relay information. We are going to observe these structures to see what makes them unique. 

b) Instruct students to assemble in pairs and obtain a slide of neurons. Share that they will observe these cells under the microscope, and sketch several of them under each magnification (4x, 10x & 40x) in their lab books. Finally, instruct students to develop and record assumed/creative names for the structures that are prominent on the cell sketches and to record hypothesized/proposed functions next to each name. Encourage students to use the post video discussion to develop ideas of cell part  functions. 

c) Discuss students observations, names and proposed functions post activity. 

Standards Covered:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

SP2- Developing and using models.

Explain

20 minutes

Section Primer: 

           The Neuron is a specialized cell committed to signal transmission in the brain and body and is comprised of several structures that allows it to perform this function by its natural design. These structures in general include: dendrites (inputs), soma (cell body), axon (transmission body), and axon terminal branches. Said structures of the neuron allows for it to transmit messages in the following way:

a) the dendrites receive chemical messengers through a synapse from an axon terminal button.

b) the axon fires an action potential along its length

c) when the action potential reaches an axon terminal button, it causes the release of a  neurotransmitter chemicals to merge with the membrane of the terminal end

d) and release the neurotransmitter chemicals into the synaptic cleft (gap), where they diffuse over to a dendrite of the recieving neuron.

Section Sequence:

           In this section of the lesson, my goal is to bring clarity of function to the structures of neurons that students observed in the exploratory section of this lesson. This activity proceeds as follows:

a) Slide 3: State: Let's explore some technical terminology associated with the sketches of the cells that we recorded in our lab books earlier. Instruct for students to use the content of the video to affix terms and definitions to the illustrations in their lab books (in a different color ink than their proposed names and functions recorded in the Explore section). Play the following for notes:

                       

b) Slide 4: Post video, discuss how students' implications of parts discussed and recorded previously compares and contrasts to the actual functions of the neuron parts developed in the video. Use the diagram on the screen to iterate correct labeling and function therein.  

Standards Covered:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

SP2- Developing and using models.

 

Extend

15 minutes

Section Primer: 

        Human Epithelial Cells are designed to line and protect the body's tissues that it covers. As it differs in function to other cells, it has a unique structure that permits it to perform its job well compared to others, while permitting it execute some of the same life sustaining functions. In this section of the lesson, students examine a magnified image of an epithelial cell that lines the inner cheek to compare and contrast to their observations of the neurons and further their understanding in the form and function concept. 

Section Instructional Sequence: 

         This section of the lesson proceeds as follows:

 a) Slide 5: State: Now that we understand that neurons are unique in structure and function, let's compare them to another cell found in the human body to see how similar and different neurons are to the body parts, they communicate with.

b) Project an image of epithelial cells from the inner check and its function. Instruct for students to sketch it next to the neuron and to  compare and contrast its structure and function to that of a neuron. 

c) Ask: What does it mean to be a specialized cell? Discuss.

d) Explain why neurons are specialized cells and how their form aids in their function. Discuss.

Standards Covered:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

SP2- Developing and using models.

 

Evaluate

15 minutes

Section Instructional Sequence:

       In this section, my goal is to have students reflect on the form and function of the neuron. This part of the lesson of the proceeds as follows:

a) Slide 6: Provide students with a copy of the following: Baylor's What is Neuron Module (Page 6) and instruct for them to complete the tasks indicated on the worksheet. Circulate and monitor for accuracy of work and collect at the completion of class. 

As an alternative, students can be presented with models of neurons (like those utilized The Nerve of Stem Cell 2 Lesson) and instructed to label the parts and function of the models independent of their recorded notes. See Student Labeling images for examples. 

 Standards Covered:

HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. 

SP2- Developing and using models.