THE EVOLUTION OF PROSTHETIC DEVICES

Introduction

Prosthetic devices replace human body parts, and they have probably been around almost as long as humans have. A prehistoric man who lost a foot in a struggle with a sabertooth tiger, for example, may have tied part of a tree branch to his leg to help him walk. Early prosthetic devices are often described in writings or in paintings from ancient cultures. However, major improvements did not occur until scientific discoveries and new manufacturing methods led to better designs and materials.

Today nearly 200 different body parts can be replaced by artificial parts. Artificial teeth are prosthetic devices. Do you know someone who uses false teeth or who has an artificial tooth implant? Hundred of years ago, many different materials were tried to replace lost teeth, including wood. Do you wear eyeglasses or contact lenses? Although they do not actually replace part of the eye, they enhance vision. However, people who have cataracts-clouded lens tissue in the eye-may choose to have surgery to replace the lens and clear their vision. Do you know someone who has had a heart transplant? Because donors are limited and the waiting lists are long, sometimes people are given an artificial heart to keep them alive until a real heart becomes available.

Prosthetic devices continue to emerge as new techniques and materials are developed. Can you imagine how they might be used in the future?

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Your Task

For this WebQuest, your job is to investigate the evolution of prosthetic devices. To demonstrate what you have learned, you will answer the questions included here. You will also complete one of the activities described at the end of this WebQuest.

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Process

Read through the following questions. Then research the Internet resources that are provided for you. As you explore the sites, look for answers to the questions. Keep a record of any sites where you find answers by noting the title and URL (Internet address). For example:

            (title) Technology Student Association
            (URL) www.tsaweb.org

1. Which of our early presidents had trouble finding false teeth that would work for him?
   
   
2. Out of which materials did the Etruscans make the first false teeth?
   
   
3. The earliest record of an artificial limb is of a prisoner circa 500 B.C. who escaped his chains by cutting off a body part. What was the body part and of what material was its replacement?
   
   
4. What was the first hearing aid? How do you think it worked to improve hearing?
   
   
5. How does a cochlear implant differ from a modern hearing aid?
   
   
6. When and where were the first eyeglasses used?
   
   
7. When someone has a lens replaced because of cataracts, what is embedded in the lens of the special glasses worn by the patient?
   
   
8. Which type of fluid power system is used in an artificial heart?
   
   
9. Brain chips are being developed to help people who are paralyzed. How do the chips work?
   
   
10. The current retina prothesis contains up to 16 electrodes for stimulating the retina. About how many electrodes do the developers believe the device will eventually have?

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Internet Resources

Visit the Web sites listed here to find information that will enable you to answer the questions. You may use additional sites if you wish. Be sure to keep a record of any sites you use.

• Prosthetics History is an article with some interesting stories about the history of prosthetics. Be prepared, there are graphic descriptions.
  
  
• False Teeth provides a brief history of their use.
  
  
• Hearing Aids Through the Ages offers answers to frequently asked questions and history about hearing aids.
  
  
• The History of Eyeglasses tells some interesting stories about their development.
  
  
• Discovery Channel: Discovery Health Tools—cochlear implants gives detailed information about cochlear implants and how doctors insert them in the ear. The site includes many drawings.
  
  
• National Institute on Deafness and Other Communication Disorders: Cochlear Implants provides basic information about implants.
  
  
• National Review of Medicine: Bionic technology offers hope to diabled describes how researchers hope to help people using brain implants.
  
  
• Advanced Biomedical Technology Research: Artificial Retina—How does the retinal prosthesis work? is about microchip implants being used to help visually impaired people see again.
  
  
• HowStuffWorks: How Artificial Hearts Work explains the technology behind artificial hearts.
  
  

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Activities

Several activities are described below. Complete one of these activities (your choice) to demonstrate the understandings you've gained by going on this WebQuest.

• Design a simple prosthetic device that will help someone do a task, such as reach items on a high shelf.
  
  
• Create a poster illustrating a common prosthetic device. Explain how it works.
  
  
• Research and write an article or create a display about how a particular person overcame a disability and went on to great success in his or her chosen field. Ludwig van Beethoven, Helen Keller, Erik Weihenmayer, and Ray Charles are examples. Be sure to keep a record of the sources you use.
  
  
• Experiment with different designs for an ear trumpet. Of what significance is its shape or size? Make a model or a finished drawing of the most effective design. Explain why you chose that design in a paragraph.
  
  
• A megaphone resembles an inverted ear trumpet. Why do you think this design would work well to increase the volume of a speaker's voice? Do some research and experiments and write a report on your findings. Be sure to cite your sources.

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