Curricular Unit: Floppy Heart Valves

Contributed by: VU Bioengineering RET Program, School of Engineering, Vanderbilt University

Two images: An eight-member family poses for a photograph; the family includes people of all ages, kids to grandparents. A color-coded U.S. map indicates the heart disease death rates, 2008-2010, for adults aged 35+noted by the darkness of each county using a scale of five shades of red.
Heart disease is a major cause of death for U.S. adults, affecting many families.
copyright
Copyright © (top) 2004 Microsoft Corporation, One Microsoft Way, Redmond, WA 98052-6399 USA. All rights reserved. (bottom) 2014 National Vital Statistics System and National Center for Health Statistics http://office.microsoft.com/en-us/images/results.aspx?qu=family&ex=1#ai:MP900407131| http://www.cdc.gov/dhdsp/data_statistics/fact_sheets/images/fs_heart_disease.png

Summary

Students are presented with an engineering challenge that asks them to develop a material and model that can be used to test the properties of aortic valves without using real specimens. Developing material that is similar to human heart valves makes testing easier for biomedical engineers because they can test new devices or ideas on the model valve instead of real heart valves, which can be difficult to obtain for research. To meet the challenge, students are presented with a variety of background information, are asked to research the topic to learn more specific information pertaining to the challenge, and design and build a (prototype) product. After students test their products and make modifications as needed, they convey background and product information in the form of portfolios and presentations to the potential buyer.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

Engineers look into ways to improve problems that humans face by developing solutions, and then researching, building, testing and redesigning those solutions to improve upon the initial design. Often what is needed does not exist, so it is up to engineers to develop novel materials, structures or procedures to solve the problems. Bioengineers perform all of these tasks, but with a focus on biological materials, processes or chemicals. In this case, student groups are challenged to develop a material that mimics the behavior and mechanical properties of aortic valves. To do this, students study the problem, learn as much about heart valves as they can, and apply their knowledge towards the design, building and testing of a material and model that meets the buyer's needs.

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High School Lesson
What Do I Need to Know about Heart Valves?

Students are presented with the unit's grand challenge problem: You are the lead engineer for a biomaterials company that has a cardiovascular systems client who wants you to develop a model that can be used to test the properties of heart valves without using real specimens.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Medical technologies include prevention and rehabilitation, vaccines and pharmaceuticals, medical and surgical procedures, genetic engineering, and the systems within which health is protected and maintained. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Design problems are seldom presented in a clearly defined form. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Technological problems must be researched before they can be solved. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Explore the anatomy of the heart and describe the pathway of blood through this organ. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Describe the biochemical and physiological nature of heart function. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Explain the relationship between the properties of a material and the use of the material in the application of a technology. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Unit Overview

This "legacy cycle" unit is structured with a contextually based Grand Challenge followed by a sequence of instruction in which students first offer initial predictions (Generate Ideas) and then gather information from multiple sources (Multiple Perspectives). This is followed by a Research and Revise phase as students integrate and extend their knowledge through a variety of learning activities. The cycle concludes with formative (Test Your Mettle) and summative (Go Public) assessments that lead students towards answering the Challenge question. See below for the progression of the legacy cycle through the unit. Research and ideas behind this way of learning may be found in How People Learn: Brain, Mind, Experience and School (Bransford, Brown & Cocking, National Academy Press, 2000); see the entire text at http://www.nap.edu/openbook.php?isbn=0309070368.

The legacy cycle is similar to the engineering design process in that they both involve identifying an existing societal need, applying science and math to develop solutions and using the research conclusions to design a clear, conceived solution to the challenge. Though the engineering design process and the legacy cycle both result in viable solutions, each focuses differently on how the solution is devised and presented. See an overview of the engineering design process in the engineering design handout in the final activity, or at http://www.nasa.gov/audience/foreducators/plantgrowth/reference/Eng_Design_5-12.html#.VDSAGvldUnE.

In What Do I Need to Know about Heart Valves?(lesson 1), students are introduced to the challenge question and exposed to some basic information relevant to the topic of heart valve tissue. This supplies the Challenge, Generate Ideas, and Multiple Perspective portions of the legacy cycle. Students wrap up the lesson by researching heart valve mechanics and valve tissue anatomy and details. These activities represent the Research and Revise portion of the legacy cycle. In The Mighty Heart associated activity, student groups dissect sheep hearts to see and feel its structure, including valves, and learn more in-depth information about valves.

In Elasticity & Young's Modulus for Tissue Analysis (lesson 2), students learn about the forces that act on heart valve tissue, as well as elasticity, stress, strain, Young's modulus and how to calculate Young's modulus for materials. They complete some practice problems to solidify their understanding. In the Does My Model Valve Stack up to the Real Thing? associated activity, students research materials suitable for their model valves. They test possible materials to evaluate them for similarities to real heart valves. Then they design and test their prototype heart valve models. Students refine their models after testing and before presenting the information to the teacher and class as an information packet. The work accomplished in this activity represents the Test Your Mettle and the Go Public portions of the legacy cycle.

Unit Schedule

Plan on the unit taking seven 50-minute class periods, according to the following schedule:

A four-column table with the column headers: Day, Document #, Curriculum Document Title, Time Required. During Days 1-2, lesson 1: What Do I Need to Know about Heart Valves? takes 100 minutes; during Day 2, activity 1: The Mighty Heart takes 45 minutes; during Day 4, lesson 2: Elasticity & Young's Modulus for Tissue Analysis takes 50 minutes; during Days 5-7, activity2: How Does My Model Valve Stack up to the Real Thing? takes 150 minutes.

Assessment

In the final activity, as the final summative assessment for this unit, students create and present informational portfolios that may include brochures, posters and other graphics, as well as information about their prototype heart valve models (including research, pictures, data and analysis).

Contributors

Michael Duplessis

Copyright

© 2013 by Regents of the University of Colorado; original © 2012 Vanderbilt University

Supporting Program

VU Bioengineering RET Program, School of Engineering, Vanderbilt University

Acknowledgements

The contents of this digital library curriculum were developed under National Science Foundation RET grant nos. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: September 7, 2017

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