The Business of the Busy-CNS!

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Objective

Students will follow precisely a complex multistep procedure and analyze the specific results to learn how to identify the parts & describe the functions of the Central Nervous System.

Big Idea

The Central Nervous System is a highly trafficked area of the body that is analogous to the efficiency of a well constructed set of roadways.

Introduction

Lesson Background & Justification:

     The nervous system consists of the brain, spinal cord, and a complex network of neurons. This system is responsible for sending, receiving, and interpreting information from all parts of the body.  The Central Nervous System (CNS), which consists of the brain and spinal cord is the processing center for the nervous system. It receives information from and sends information to the peripheral nervous system (nerve cells that iterate the body).In this lesson, students learn to explain the coordinating efforts between the organs of the CNS in the effort to comprehend later units which explore these altered or diseased CNS regions in detail. This lesson, the fourth of a five lesson unit, links with the unit's fifth lesson to explore engineering practices that may potentially lead to the replacement of damaged or diseased CNS organs as students learn the specific anatomy and physiology of this critical system.  

Lesson Preparations:

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

a) 6 vials of Drosophila Melangaster larvae (3rd instar stage).  

b) A class set of protective wear (non-latex gloves, lab coats and safety glasses).

c) A class set of rulers.

d) Student lab books.

e) A class set (one per pair) of dissection tools (consists of dissection scissors, dishes with small shallow wells and tweezers).

f) 1x PBS Buffer.

Common Core and NGSS Standards:

SP6- Constructing explanations (for science) and designing solutions (for engineering).

HS-LS1-2: Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

RST.11-12.3: Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.

Standards Rationale:

       Engineering investigations include analysis of data collected in the tests of designs. This allows comparison of different solutions and determines how well each meets specific design criteria-that is, which design best solves the problem within given constraints. Like engineers, budding scientists must gain command of engineering practices and lab procedures to make interpretation of data generated in their investigations and analysis of proposed solutions more efficient and effective. This lesson engages students in the process of following specific procedures to extract a factor in the overall engineering equation as this skill set is a critical component to the designing stage for engineers; bioengineers in this scenario.

Engage

15 minutes

Section Primer:

        Quadriplegia, also known as tetraplegia , is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all their limbs and torso. This condition, a consequence of localized damage to the CNS is introduced to students to pique their interest levels so that they may pursue the anatomy and function of the CNS with a purpose hereafter. 

Section Sequence:

        In this section of the lesson, my goal is to hook students onto the lesson and use students' interest levels to set the stage for their upcoming investigations. This section progress as follows: 

a) Slide 1: State "It's story time everyone. We are going to watch a video and essentially build a summary of the story being told about the young lady on the screen. I am going to begin and end the story using the prompts on the screen (point these out), but you as a class will fill in the middle of the story/summary after learning a little bit about the young lady in the story." I proceed to play the following video:         

       

b) Post-video, execute step a. Allow for as many students to verbally add to the story as possible before concluding. 

c) Ask: "Based on our story, how would you define a quadriplegic?" and discuss responses with the aid of the illustration of the CNS displayed. 

d) State: "Let's explain this condition a little better by examining the impacted area closer". Play the video until 1:35 minutes and discuss the details of the condition further. 

       

Standards Covered:

HS-LS1-2: Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. 

Explore

75 minutes

Section Primer:

        Drosophila melanogaster is a species of fly that is known generally as the common fruit fly or vinegar fly. This species has been utilized in a host of studies as a model organism to study human genetics, developmental biology and physiology. Like humans, this invertebrate develops a central nervous system similar to the structure to that of humans. As such, I utilize this organism to investigate spinal cord/body length ratios to compare to human data and to serve as a variable/investigative constraint to solve an bio-engineering problem.

Section Sequence:  

      In this section, my goal is to get students to approach the problem of creating a replacement organ of the CNS and to think critically about established data to aid in the problem's investigative approach. I sequence this section as follows:

a) Slide 2: Ask "Imagine for a moment that we could replace someone’s or something’s spinal cord, what would we need to know or do before successful implantation? How do we know that we have built the ideal spinal cord to fulfill its function?" Let's start simple. Discuss and record ideas on the board (To do list). Be certain to direct conversation to include spinal cord length on the list.  

b) Circle spinal cord length and inform students that we will start here. Ask students questions that elude to the spinal cord's length as an important variable in the engineering process. Use images on the screen to emphasize or to direct students attention to proportionality. 

c) Slide 3: Direct students attention to the data on the screen and ask how this data may help us to evaluate if we have the proper spinal cord length for the patient. Discuss. Then tell students to consider using a model organism to provide credibility to the spinal cord/body length ratio idea. Ask how they would use the same data to emphasize that this is a constant across species and thus an ideal quantitative measure for engineering constraints. Discuss.

d) Share that we will use the fruit fly to help us in our proposed design process. Provide background information on the fruit fly and why its a credible model for human studies. Continue to show the fly's similarity in spinal cord locale by playing the following: 

 

                  

e) Slide 4: Ask "What's our game plan?" Allow for the class to discuss as a whole and come up with a singular plan that all will pursue. Record on the board and direct students to record in their lab books. 

f) Prime students for the lab with materials and show the following instructional video before students pursue their dissections. 

      

g) Provide guided assistance when needed as students investigate and collect data. Discuss discoveries with student pairs as they finish and then again with the class when all are done as a whole. 

Standards Covered:

SP6- Constructing explanations (for science) and designing solutions (for engineering).

HS-LS1-2: Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. 

RST.11-12.3: Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.