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The Brain: Our Sense of Self

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Teacher's Guide

Lesson 3—Explore/Explain

Inside Information

At a Glance

Overview

Students construct two pathways for information flow through the human nervous system. First, they build a pathway for an involuntary action, or reflex. Students discover that this pathway does not require information transfer to and from the brain. Next, students build a pathway for a voluntary response. They discover that voluntary responses include an element of choice. Since the brain is required to make a choice, voluntary response pathways involve information transfer to and from the brain.

Major Concepts

The body receives and delivers information through the nervous system. The nervous system is an interconnected set of specialized parts, including the brain, the spinal cord, and nerve cells outside the brain and spinal cord. Information flows in one direction through a nerve cell. Reflex pathways lead to rapid, involuntary responses and include only the spinal cord and nerve cells outside the brain and spinal cord. Voluntary response pathways involve choice, and thus include the brain as well as the spinal cord and nerve cells outside the brain and spinal cord.

Objectives

After completing this lesson, students will be able to

Teacher Background

Refer to the following sections in Information about the Brain:

  1. 4 Cells of the Nervous System
  2. 4.1 Neurons
  3. 4.3 Transmission of nerve impulses: electrical transmission
  4. 5 The Brain
  5. 5.3 The brain and sensory input
  6. 5.4 The brain and motor output
  7. 6 The Spinal Cord
  8. 6.1 Structure of the spinal cord
  9. 6.2 Spinal cord functions

In Advance

Web-Based Activities
Activity Web Version?
1 No
2 Yes
3 No
Photocopies
Activity 1 Master 3.1, Two Types of Cells, 1 transparency
Activity 2

Web Version
Master 3.2, Pathway-Building Worksheet, 1 per student

Print Version
Master 3.3(a, b, c), Neuroscience Reference Manual, 1 copy per group
Master 3.4, Building a Reflex Pathway, 1 copy per group, plus 4 transparencies
Master 3.5, Building a Voluntary Response Pathway, 1 copy per group, plus 4 transparencies

Activity 3 None required.
Materials
Activity 1 Overhead projector and screen
Activity 2

Web Version
Computers with Internet access

Print Version
Overhead projector and screen
Three water-soluble transparency pens of different colors
Colored pencils, three different colors per group

Activity 3 None required.

Preparation

Activity 1
Set up overhead projector and screen.

Activity 2, Web Version
Reserve computer lab, or set up computers with Internet access in classroom.
Before class, go to the Web page http://science.education.nih.gov/supplements/self/student. Clicking on the link to “Lesson 3—Inside Information” brings up the unit’s “desktop,” which contains a link to “Inside Information.” Work through both pathways (reflex and voluntary movement) to familiarize yourself with the activity.

Activity 2, Print Version
Set up overhead projector and screen.
Staple sets of Masters 3.3(a, b, c) together to form Neuroscience Reference Manuals.
Activity 3
None required.

Procedure

Activity 1: Information Flow (for Print and Web)

  1. Begin the lesson by displaying a transparency of Master 3.1, Two Types of Cells, on the overhead projector. Ask students to make observations about the two cells.

Focus discussion on similarities and differences between the two cells. Students may say that the top cell is smooth and round, while the bottom cell is long and thin. They may comment that although both cells have a cell body and a nucleus, there appear to be some “extra” parts sticking out of the bottom cell.

  1. Explain to the class that the top cell is the most common type of animal cell, such as a skin cell. The bottom cell is a special cell that passes information through the body. It is a nerve cell, or neuron.
assessment icon
Assessment:
Listen to student responses to assess their understanding that information flows in only one direction through neurons. This concept is key to the following activities.

Explain briefly that a neuron is made up of three parts: the dendrites, the cell body, and the axon.

  1. Ask students to stand and form a line around the classroom. Explain that they will model information flow through a neural pathway.

A neural pathway is a path of information flow through the body. Each student represents one neuron along the pathway.

  1. Ask students to hold out their arms, forming a fist with their right hand and leaving their left hand open.

Students should stand close to one another but leave a space between adjacent hands. Explain that as neurons, the open left hand of each student represents their axon end, and their right fist represents their dendrite end.

  1. Tell students that they will be passing information through their model pathway by using their open hand to tap the fist of the person next to them.
National Science Education Standards icon
Content Standard C:
All organisms are composed of cells—the fundamental unit of life. Living systems at all levels of organization demonstrate the complementary nature of structure and function. Specialized cells perform specialized functions in multicellular organisms.

Start the flow of information through the pathway by tapping the fist of the rightmost student of the line with your left hand. Each student should pass the information along by using their axon (left hand) to tap the dendrite (right fist) of the student next to them. Allow the information to be passed through the entire line of students.

  1. Now ask a student in the middle of the line to face the opposite direction from the rest of the line, leaving the same hands open and fisted. Once again, start the flow of information by tapping the fist of the rightmost student in the line. What happens to the signal?

To make the point of directional information flow, you may want to reinforce the idea that the open hand can only send information and the fist can only receive information. The signal should stop at the student facing the opposite direction from the rest of the line.

  1. Ask students what this experiment suggests about information flow through neurons.

Information flows through neurons in one direction only.

Web activity icon

Activity 2: Inside Information

For classes using the Web-based version of this activity:

National Science Education Standards icon
Content Standard C:
Behavior is one kind of response an organism can make to an internal or environmental stimulus.

Part 1, A Reflex Pathway

  1. Ask students to explain the difference between a voluntary response and an involuntary response.

A voluntary response is an action we choose to perform. We do not choose to perform an involuntary response; instead, our bodies respond without a conscious choice.

  1. Ask students to provide examples of voluntary and involuntary responses.

Voluntary responses include walking, talking, eating, or reading books. Involuntary responses include changes in heartbeat, breathing, digestion, or blinking.

  1. Explain to the class that they will investigate an involuntary response known as a reflex action. Ask, “What is a reflex action?”

Students should have a general understanding that a reflex involves a quick, automatic response by their bodies to an input from the environment.

  1. Your students probably are familiar with the knee-jerk reflex. Ask for student volunteers to describe and/or demonstrate this reflex.

Students may describe the knee-jerk reflex as something they have experienced when they visit the doctor. The doctor taps below their kneecap with a small hammer, and their leg kicks out. Some students may wish to demonstrate this reflex on their own knee. Alternately, you may choose to demonstrate the reflex on yourself by sitting on your desk and hitting your knee. In addition, you may wish to have all students try out this reflex on themselves.

Some students may be unable to get the knee-jerk reflex to work on themselves and may become concerned that there is something wrong with them. Reassure these students by explaining that finding the precise location to tap below the kneecap can be difficult for nonphysicians. Furthermore, if students consciously tighten their leg muscles, the knee-jerk reflex either may not occur or may occur only subtly.

assessment icon
Assessment:
Collecting the completed masters from students at the conclusion of this lesson provides an opportunity for formal assessment of students’ understanding of neural pathways.
  1. Give one copy of Master 3.2, Pathway-Building Worksheet, to each student.

Explain to students that they will use a Web interface to construct the neural pathway that controls the knee-jerk reflex. After they have constructed the neural pathway, they will draw it and answer questions about it on Master 3.2.

  1. Divide the class into groups of two or three students each. Direct groups to computer stations.
  2. Ask groups to open their Internet browser, go to http://science.education.nih.gov/supplements/self/student, and click on “Lesson 3—Inside Information” to bring up the unit’s “desktop.” Students can then click on the link to “Inside Information” and then the link to the reflex pathway.
  3. Instruct students to listen to the audio introduction to the activity.

Students may replay the audio at any time by clicking on the “Replay Audio” button.

  1. Ask students to click on the link for the “Neuroscience Reference Manual.” Explain that the manual contains essential information for constructing neural pathways.

Point out several sections of the manual that will be helpful to students as they construct their neural pathways. Part 1 of the manual describes the parts of the nervous system; Part 2 describes neural signaling and the three main types of neurons; and Part 3 contains details about reflex actions and voluntary actions.

Tip from the field test: Introducing the reference manual before students start working emphasizes the importance of this resource and encourages students to use this information to help them complete the activity.

  1. Explain to students that they may navigate through the Neuroscience Reference Manual by clicking on the section names in the manual’s Table of Contents. They may return to the Table of Contents by clicking on the “Back to Main Menu” hotlinks at the end of each section.

Encourage students to take a minute to explore this navigation system.

  1. Explain to students that to construct a neural pathway, they will need to select the correct body parts and neurons and place them in the correct position in the figure. Walk students through the process of placing and removing body parts and neurons in the figure on the right side of the Web screen.

Placing and removing body parts:

  • To place a body part on the figure, click on the appropriate body part “box” on the left side of the screen. The body part will appear in the figure.
  • To remove the body part from the figure, click on the body part in the figure or in its box.

Placing and removing neurons:

  • Neurons must be placed across two connection points (red circles) in the body.
  • To place a neuron in the figure, first select the appropriate type of neuron by clicking on its “box” on the left side of the screen. After selecting a neuron, click on a connection point in the figure to place the dendrite end of the neuron at that point. Clicking on a second connection point places the axon end of the neuron at the second point, its target site.
  • To remove a neuron from the figure, click on the neuron within the figure.

Tip from the field test: Spending time discussing these basic instructions with the class decreases confusion and allows students to focus on the lesson’s content and complete the activity more quickly.

  1. Tell students that they are ready to construct the neural pathway for the knee-jerk reflex. Instruct groups to complete the pathway using only those parts that are involved directly in the pathway.

Students should read, interpret, and evaluate information in the Neuroscience Reference Manual to determine how to construct the pathway. Students should pay particular attention to the types of neurons described in Part 2 of the manual, and to the “Reflex Actions” section in Part 3 of the manual. As student groups work, walk around the classroom to monitor their progress. Be available to answer questions, but encourage students to consult the appropriate section(s) of the Neuroscience Reference Manual. Students can

  • replay the reflex animation by clicking on the “Replay Animation” button,
  • test their pathway by clicking on the “Test Pathway” hammer, and
  • reset the entire pathway by clicking on the “Reset Pathway” button.
Reflex pathway

A correctly completed pathway should have the following attributes:

  • The pathway should include only the spinal cord, one sensory neuron, and one motor neuron.
  • The sensory neuron should have its dendrites on the thigh and its axon terminals on the pelvic region of the spinal cord.
  • The motor neuron should have its dendrites on the spinal cord and its axon terminals on the thigh muscle.

If the pathway is correct, the following series of events will take place on the Web page when students click on the “Test Pathway” hammer:

  • When the kneecap is hit with the hammer, a spark, representing neural information, travels from the thigh muscle, through the sensory neuron, to the spinal cord.
  • At the spinal cord, the spark transfers to the motor neuron.
  • The spark travels through the motor neuron to the thigh muscle, and the leg kicks out.

Students must use the correct components of the pathway and place them in the correct orientations. This leads to the discovery that information can only travel through a neural pathway in one direction.

  1. If the pathway is built incorrectly, students will receive one of three error messages when they test the pathway, and the Neuroscience Reference Manual will open to the appropriate section.

If the pathway itself is constructed correctly but the spinal cord is not included, or inappropriate body parts (heart, lung, liver) are included, the Web page will provide the following error message:

“Your pathway is not correct. Are you using the right body parts? Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 1: The Central Nervous System.

If the neurons of the pathway are correct but placed in the wrong orientation, the Web page will provide the following error message:

“Your pathway is not correct. Are the neurons placed correctly? Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 2: Signaling and Neurons.

If the neurons of the pathway are incorrect or the brain is included in the pathway, the Web page will provide the following error message:

“Your pathway is not correct. Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 3: Neural Pathways.

  1. When students complete the pathway, remind them to answer the questions on Master 3.2, Pathway-Building Worksheet, to describe the pathway they have built.

At the end of Part 1, ask students to keep Master 3.2, Pathway-Building Worksheet, for use in Part 2 of Activity 2.

assessment icon
Assessment:
Assess students’ understanding by listening to their explanations and reasoning.
  1. Reconvene the class. Through discussion, encourage students to examine their pathway-building process critically. Was their group able to make a pathway that worked? What types of pathways did not work? Why?

Students may have made errors as they constructed the correct pathway. Encourage them to share their experiences and explain why certain configurations did not work. At the end of the discussion, students should be able to construct the knee-jerk reflex pathway correctly and describe the flow of information through it.

Students will find that the heart, lungs, liver, and brain were not needed to complete the knee-jerk reflex pathway. In fact, the pathway was marked “Incorrect” if any of these parts were included. It was necessary to leave the heart, lungs, and liver out of the pathway because these body parts are not part of the nervous system. It was necessary to exclude the brain from this pathway because the brain is not involved in the transfer of information in this example.

Part 2, A Voluntary Response Pathway

  1. Instruct groups to return to their computers. Ask them to open up their Internet browser and go to the Web page http://science.education.nih.gov/supplements/self/student and click on “Lesson 3—Inside Information.” This brings up the unit’s “desktop,” from which students should click on the link to “Inside Information.” Students then click on the link to the voluntary movement pathway.
  2. Explain to students that they are to construct a neural pathway for the voluntary leg movement involved in kicking the soccer ball. Instruct groups to complete the pathway using only those parts that are involved directly in the pathway.

Explain to the class that the path of information flow begins with the eyes; that is, seeing the soccer ball coming toward them. The response is moving the leg to kick the ball.

Students should read, interpret, and evaluate information in the Neuroscience Reference Manual to determine how to construct the pathway. Students should pay particular attention to the types of neurons described in Part 2 of the manual, and to the “Voluntary Actions” section in Part 3 of the manual. As student groups work on their pathways, walk around the classroom to monitor their progress. Be available to answer questions, but encourage students to consult the appropriate section(s) of the Neuroscience Reference Manual. Students can

  • replay the animation by clicking on the “Replay Animation” button,
  • test their pathway by clicking on the “Test Pathway” soccer ball, and
  • reset the entire pathway by clicking on the “Reset Pathway” button.
Voluntary response pathway

A correctly completed pathway should have the following attributes:

  • The pathway includes the brain, the spinal cord, one sensory neuron, one interneuron, and one motor neuron.
  • The sensory neuron should have its dendrites on the eye and its axon terminals on the brain.
  • The interneuron should have its dendrites on the brain and its axon terminals on the pelvic region of the spinal cord.
  • The motor neuron should have its dendrites on the spinal cord and its axon terminals on the thigh.

If the pathway is correct, the following series of events will take place on the Web page when students click on the “Test Pathway” soccer ball:

  • As the soccer ball falls toward the figure’s foot, a spark, representing neural information, travels from the eye, through the sensory neuron, to the brain.
  • At the brain, the spark transfers to the interneuron.
  • The spark travels through the interneuron from the brain to the spinal cord.
  • At the base of the spinal cord, the spark transfers to the motor neuron.
  • Finally, the spark travels through the motor neuron to the thigh muscle, and the foot kicks the soccer ball.

Students must use the correct components of the pathway and place them in the correct orientations. This leads to reinforcing the discovery students made in Activity 1 of this lesson, that information can only travel through a neural pathway in one direction.

  1. If the pathway is built incorrectly, students will receive one of three error messages when they test the pathway, and the Neuroscience Reference Manual will open to the appropriate section.

If the pathway itself is constructed correctly but the spinal cord is not included, or inappropriate body parts (heart, lung, liver) are included, the Web page will provide the following error message:

“Your pathway is not correct. Are you using the right body parts? Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 1: The Central Nervous System.

If the neurons of the pathway are correct but placed in the wrong orientation, the Web page will provide the following error message:

“Your pathway is not correct. Are the neurons placed correctly? Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 2: Signaling and Neurons.

If the neurons of the pathway are incorrect or the brain is not included in the pathway, the Web page will provide the following error message:

“Your pathway is not correct. Check the Neuroscience Reference Manual.”

The Neuroscience Reference Manual will open to Part 3: Neural Pathways.

  1. When students complete the pathway, remind them to answer the questions on Master 3.2, Pathway-Building Worksheet.

Students use Master 3.2 to answer questions about the pathways built in Parts 2 and 3 of the lesson. At the end of Part 3, you may wish to ask them to hand in Master 3.2.

  1. Reconvene the class. Through discussion, encourage students to examine their pathway-building process critically. Was their group able to make a pathway that worked? What types of pathways did not work? Why?
assessment icon
Assessment:
Assess students’ understanding by listening to their explanations and reasoning.

Students may have made errors as they constructed the correct pathway. Encourage them to share their experiences and explain why certain configurations did not work. At the end of the discussion, students should be able to construct the voluntary leg movement pathway correctly and describe the flow of information through it.

Students will find that the heart, lungs, and liver were not needed to complete the voluntary movement pathway. In fact, the pathway was marked “Incorrect” if any of these parts were included. It was necessary to leave these parts out of the pathway because these body parts are not part of the nervous system. While the heart, lungs, and liver are all important for keeping a body alive, they are not directly involved in the transfer of information through the voluntary movement pathway.

Explain to students that although they used only one type of each neuron in this example, in reality, millions of neurons are used to elicit this response.

print activity iconFor classes using the print verson of this activity:

Part 1, A Reflex Pathway

  1. Ask students to explain the difference between a voluntary response and an involuntary response.
National Science Education Standards icon
Content Standard C:
Behavior is one kind of response an organism can make to an internal or environmental stimulus.

A voluntary response is an action we choose to perform. We do not choose to perform an involuntary response; instead, our bodies respond without a conscious choice.

  1. Ask students to provide examples of voluntary and involuntary responses.

Voluntary responses include walking, talking, eating, or reading books. Involuntary responses include changes in heartbeat, breathing, digestion, or blinking.

  1. Explain to the class that they will investigate an involuntary response known as a reflex action. Ask, “What is a reflex action?”

Students should have a general understanding that a reflex involves a quick, automatic response by their bodies to an input from the environment.

  1. Your students are probably familiar with the knee-jerk reflex. Ask for student volunteers to describe and/or demonstrate this reflex.

Students may describe the knee-jerk reflex as something they have experienced when they visit the doctor. The doctor taps below their kneecap with a small hammer, and their leg kicks out. Some students may wish to demonstrate this reflex on their own knee. Alternately, you may choose to demonstrate the reflex on yourself by sitting on your desk and hitting your knee. In addition, you may wish to have all students try this reflex on themselves.

Some students may be unable to get the knee-jerk reflex to work on themselves and may become concerned that there is something wrong with them. Reassure these students by explaining that finding the precise location to tap below the knee can be difficult for nonphysicians. Furthermore, if students consciously tighten their leg muscles, the knee-jerk reflex either may not occur or may occur only subtly.

  1. Explain to students that they will be working in groups to construct the neural pathway that controls the knee-jerk reflex. Divide the class into groups of two or three students each.
  2. Give stapled sets of Master 3.3(a, b, and c), Neuroscience Reference Manual, to each group.

Explain that the Neuroscience Reference Manual contains essential information for this activity. Point out several sections of the manual that will be helpful to students as they construct their neural pathways. Part 1 of the manual describes the parts of the nervous system; Part 2 describes neural signaling and the three main types of neurons; and Part 3 contains details about reflex actions and voluntary actions.

Tip from the field test: Introducing the reference manual before students start working emphasizes the importance of this resource and encourages students to use this information to help them complete the activity.

assessment icon
Assessment:
Collecting the completed masters from students at the conclusion of this lesson provides an opportunity for formal assessment of students’ understanding of neural pathways.
  1. Give each group one copy of Master 3.4, Building a Reflex Pathway. Explain to students that they will work with their group members to construct a neural pathway for the knee-jerk reflex.

Students use colored pencils to draw neurons on Master 3.4, Building a Reflex Pathway. This master contains an outline of a person with the brain, spinal cord, and thigh muscle, as well as the heart, lungs, and liver, drawn in.

  1. Give each group pencils of three different colors. Explain to students that they should use these pencils to represent the three types of neurons as they construct their pathway. Only one of each type of neuron used needs to be drawn as a representation. Instruct groups to use the Neuroscience Reference Manual to help them complete their drawings.

Students should read, interpret, and evaluate information in the Neuroscience Reference Manual to determine how to construct the pathway. Students should pay particular attention to the types of neurons described in Part 2 of the manual and to the “Reflex Actions” section in Part 3 of the manual. As student groups work, walk around the classroom to monitor their progress. Be available to answer questions, but encourage students to consult the appropriate section(s) of the Neuroscience Reference Manual before you answer.

  1. As students construct their diagrams, ask them to discuss the following questions with their group members:
    1. Why did their group choose the parts they did?
    2. How did they put those parts together?
    3. How does information flow through the pathway?

You may wish to write these questions on the board so students can refer to them. This step helps students prepare for their presentations (Step 10).

  1. When groups are finished, ask one group to diagram their reflex pathway on a transparency of Master 3.4, Building a Reflex Pathway.

Students should explain the following:

  1. Why their group chose the parts they did.
  2. How they put those parts together.
  3. How information flows through the pathway.
Reflex pathway

A correctly completed pathway should have these attributes:

If the pathway is correct, information would flow as follows:

Students should use the correct components of the pathway and place the components in the correct orientation. This leads to reinforcing the discovery they made in Activity 1 of this lesson, that information can only travel through a neural pathway in one direction.

  1. When the presentation is completed, ask the other groups if they agree with the pathway of the first group. If another group disagrees, ask a representative from that group to present their pathway using another transparency of Master 3.4.

The new representative should explain their group’s pathway to the class. Student descriptions should consist of the components, construction, and flow of information outlined above. Encourage the class to examine each pathway carefully based on the information provided in the Neuroscience Reference Manual. Does the pathway have enough parts? Too many parts? Are the parts connected in the correct way? Would information flow through the pathway correctly? Why or why not?

assessment icon
Assessment:
Assess students’ understanding by listening to their explanations and reasoning.

Allow presentations to continue until all alternate pathways have been explained to the class. Through discussion of the pathways presented, the class should be able to create a correct pathway by consensus. At the end of the discussion, all students should be able to construct the reflex pathway correctly and describe the flow of information through it.

Part 2, A Voluntary Response Pathway

  1. Give one copy of Master 3.5, Building a Voluntary Response Pathway, to each group.
  2. Explain to students that they will work with their group members to construct a neural pathway for the voluntary leg movement involved in kicking the soccer ball. Instruct groups to complete their drawings with only those parts that are involved directly in the pathway, using the Neuroscience Reference Manual as a guide.

Explain to the class that the path of information flow begins with the eyes—that is, seeing the soccer ball coming toward them. The response is moving the leg to kick the ball.

Students should read, interpret, and evaluate information in the Neuroscience Reference Manual to determine how to construct the pathway. Students should pay particular attention to the types of neurons described in Part 2 of the manual and to the “Voluntary Actions” section in Part 3 of the manual. As student groups work on their pathways, walk around the classroom to monitor their progress. Be available to answer questions, but encourage students to consult the appropriate section(s) of the Neuroscience Reference Manual before you answer.

  1. As students construct their diagrams, ask them to discuss the following questions with their group:
    1. Why did their group choose the parts they did?
    2. How did they put those parts together?
    3. How does information flow through the pathway?

Writing these questions on the board allows students to refer to them as they work. This step helps students prepare for their presentations (Step 4).

  1. When groups are finished, ask one group to diagram their voluntary response pathway on a transparency of Master 3.5, Building a Voluntary Response Pathway.

Student descriptions should include these components:

  1. Why their group chose the parts they did.
  2. How they put those parts together.
  3. How information flows through the pathway.
Voluntary response pathway

A correctly completed pathway should have these attributes:

If the pathway is correct, information would flow as follows:

Students should use the correct components of the pathway and place them in the correct order and orientation. This leads to the following discoveries: neurons are specific to a certain job, and information flows through a neural pathway in only one direction.

  1. After the presentation is completed, ask the other groups if they agree with the pathway of the first group. If another group disagrees, ask a representative from that group to present their pathway using another transparency of Master 3.5.
assessment icon
Assessment:
Assess students’ understanding by listening to their explanations and reasoning.

The new representative should explain their group’s pathway to the class. Student descriptions should consist of the components, construction, and flow of information outlined above. Students may produce a variety of incorrect answers. Encourage the class to carefully examine each pathway based on the information provided in the Neuroscience Reference Manual. Does the pathway have enough parts? Too many parts? Are the parts connected in the correct way? Would information flow through the pathway correctly? Why or why not?

Allow presentations to continue until all alternate pathways have been explained to the class. Through discussion of the pathways presented, the class should be able to create the correct pathway by consensus. At the end of the discussion, all students should be able to construct the voluntary leg movement pathway correctly and describe the flow of information through it.

Activity 3: Summing It Up (for Print and Web)

  1. The first pathway students constructed was for the knee-jerk reflex. Ask students, “If a physician tested the knee-jerk reflex on each of us, would everyone’s response be the same?”

Students should generally agree that the knee-jerk reflex would be the same for everyone tested by the physician.

  1. The second pathway students constructed was for the voluntary leg movement to kick a soccer ball. Now ask students to imagine that they are actually playing soccer. They notice that the ball is headed straight for them. What would they do?

Students may provide a variety of answers, including kicking, bouncing, or catching the ball, moving out of its way, standing still and allowing the ball to hit them, or not being on the soccer field in the first place. In general, students should answer that they would somehow interact with the soccer ball.

assessment icon
Assessment:
Asking students to write their answers to the questions in Steps 3 and 4 allows them to organize their thoughts and reflect on what they have learned in this lesson. For a formal assessment of student learning, you can review the written materials.
  1. Point out that a variety of responses was provided for the soccer ball scenario, as opposed to the same response by everyone for the knee-jerk reflex. Ask students, “Why were you able to have different responses for the soccer ball scenario?”

Students should explain that the soccer ball scenario required a voluntary response. Since voluntary responses involve choice, students were able to choose their response to the soccer ball scenario, which allowed their responses to be different from their peers’.

  1. Ask students why they were not able to choose the response to the reflex action. What is the difference between the two pathways?

Students should recall that the voluntary response pathway included the brain, while the reflex pathway did not. Since the brain is required to make a choice, students were unable to choose their response to the reflex action.


Web activity icon Lesson 3 Organizer: Web Version
Activity 1: Information Flow
What the Teacher Does Procedure Reference

Display a transparency of Master 3.1, Two Types of Cells.

  • Ask students to make observations about the two cells.
  • Explain that the top cell is a common type of animal cell.
  • Explain that the bottom cell is a nerve cell, or neuron, and that it passes information through the body.
transparency iconSteps 1–2

Ask students to stand and form a line around the classroom.

  • Explain that they will model the flow of information through a neural pathway.
  • Ask students to hold out their arms, forming a fist with their right hand and leaving their left hand open.

Steps 3–4

Tell students they will be passing information through their model pathway by using their open hand to tap the fist of the person next to them.

Step 5

Ask a student in the middle of the line to face the opposite direction from the rest of the line, leaving the same hands open and fisted.

  • Start the flow of information by tapping the fist of the rightmost student in the line.
  • Ask students what happens to the signal.
  • Ask students what this model suggests about information flow through neurons.
Steps 6–7
Activity 2: Inside Information, Part 1: A Reflex Pathway
What the Teacher Does Procedure Reference

Ask students

  • to explain the difference between a voluntary response and an involuntary response,
  • to provide examples of voluntary and involuntary responses, and
  • what a reflex action is.
Steps 1–3

Ask for student volunteers to describe and/or demonstrate the knee-jerk reflex.

Step 4
  • Give each student one copy of Master 3.2, Pathway-Building Worksheet.
  • Divide the class into groups of two or three and send groups to computer stations.
  • Direct students to the activity’s Web site.
    • Instruct students to listen to the audio introduction to the activity.
    • Have students click on the link for the “Neuroscience Reference Manual” and review its use with them.
    • Explain to students how to place and remove body parts and neurons.
Web activity iconSteps 5–11

master icon
  • Instruct groups to complete the reflex pathway using only those parts involved directly in the pathway.
  • After completing the pathway, ask students to answer the questions on Master 3.2, Pathway-Building Worksheet.
Web activity iconSteps 12–14

Reconvene the class. Discuss the following:

  • Were groups able to construct a pathway that worked?
  • What types of pathways did not work? Why?
Step 15
Activity 2: Inside Information, Part 2: A Voluntary Response Pathway
What the Teacher Does Procedure Reference

Instruct students to go to their computers and have them click on the link to this activity.

Web activity iconStep 1
  • Explain to students that they are to construct a neural pathway for the voluntary leg movement involved in kicking a soccer ball.
  • After completing the pathway, ask students to answer the questions on Master 3.2, Pathway-Building Worksheet.
Web activity iconSteps 2–4

Reconvene the class. Discuss the following:

  • Were groups able to construct a pathway that worked?
  • What types of pathways did not work? Why?
Step 5
Activity 3: Summing It Up
What the Teacher Does Procedure Reference

Ask students, “If a physician tested the knee-jerk reflex on each of us, would everyone’s response be the same?”

Step 1

Ask students to imagine that they are playing soccer.

  • The ball is heading directly for them.
  • Ask them what they would do.
Step 2

Point out that students provided a variety of responses for the soccer ball scenario, as opposed to their having the same response for the knee-jerk reflex. Ask, “Why were you able to have different responses for the soccer ball scenario?”

Step 3

Ask students why they were not able to choose the response to the reflex action. What is the difference between the two pathways?

Step 4
transparency icon= Involves using a transparency.
master icon= Involves copying a master.
Web activity icon= Involves using the Internet.

print activity icon Lesson 3 Organizer: Print Version
Activity 1: Information Flow
What the Teacher Does Procedure Reference

Display a transparency of Master 3.1, Two Types of Cells.

  • Ask students to make observations about the two cells.
  • Explain that the top cell is a common type of animal cell.
  • Explain that the bottom cell is a nerve cell, or neuron, and that it passes information through the body.
transparency iconSteps 1–2

Ask students to stand and form a line around the classroom.

  • Explain that they will model the flow of information through a neural pathway.
  • Ask students to hold out their arms, forming a fist with their right hand and leaving their left hand open.

Steps 3–4

Tell students they will be passing information through their model pathway by using their open hand to tap the fist of the person next to them.

Step 5

Ask a student in the middle of the line to face the opposite direction from the rest of the line, leaving the same hands open and fisted.

  • Start the flow of information by tapping the fist of the rightmost student in the line.
  • Ask students what happens to the signal.
  • Ask students what this model suggests about information flow through neurons.
Steps 6–7
Activity 2: Inside Information, Part 1: A Reflex Pathway
What the Teacher Does Procedure Reference

Ask students

  • to explain the difference between a voluntary response and an involuntary response and
  • to provide examples of voluntary and involuntary responses.
Steps 1–2

Tell students they will investigate an involuntary response known as a reflex action.

  • Ask, “What is a reflex action?”
  • Ask for student volunteers to demonstrate the knee-jerk reflex.
Steps 3–4

Divide the class into groups of two or three.

  • Give each student one copy of Master 3.3(a, b, and c), Neuroscience Reference Manual, and a copy of Master 3.4, Building a Reflex Pathway.
  • Explain the use of these masters.
  • Give each group three different colored pencils.
master iconSteps 5–8

Ask groups to construct their reflex pathway, focusing on

  • why they chose the parts they did,
  • how those parts were put together, and
  • how information flows through the pathway.
Step 9

Ask one group to diagram their pathway on a transparency of Master 3.4, Building a Reflex Pathway.

transparency iconStep 10

Ask the other groups if they agree with the work of this group. If any groups disagree, ask them to present their pathway and explanation.

Step 11
Activity 2: Inside Information, Part 2: A Voluntary Response Pathway
What the Teacher Does Procedure Reference

Give each group a copy of Master 3.5, Building a Voluntary Response Pathway. Groups should still have their copy of Master 3.3(a, b, and c), Neuroscience Reference Manual.

master activity iconSteps 1–2

Ask groups to construct their voluntary response pathway, focusing on

  • why they chose the parts they did,
  • how those parts were put together, and
  • how information flows through the pathway.
Step 3

Ask one group to diagram their pathway on a transparency of Master 3.5, Building a Voluntary Response Pathway.

Step 4

Ask the other groups if they agree with the work of this group. If any groups disagree, ask them to present their pathway and explanation.

Step 5
Activity 3: Summing It Up
What the Teacher Does Procedure Reference

Ask students, “If a physician tested the knee-jerk reflex on each of us, would everyone’s response be the same?”

Step 1

Ask students to imagine that they are playing soccer.

  • The ball is heading directly for them.
  • Ask them what they would do.
Step 2

Point out that students provided a variety of responses for the soccer ball scenario, as opposed to their having the same response for the knee-jerk reflex. Ask, “Why were you able to have different responses for the soccer ball scenario?”

Step 3

Ask students why they were not able to choose the response to the reflex action. What is the difference between the two pathways?

Step 4
master icon= Involves copying a master.
transparency icon= Involves using a transparency.

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