Using The Cardiovascular System To Illustrate Fundamental Laws And Principles In A Freshman Course

Ð Our Fundamentals of Bioengineering I course is organized around key physical and engineering laws and principles. A semester-long Major Project is assigned which integrates many of these principles by modeling the human systemic cardiovascular system, using both Matlab computer analysis and assembly of an analogous electrical circuit. Background Ð The new undergraduate degree program in biomedical engineering at the University of Utah accepted its first freshman class in fall 1999. An integral part of the curriculum is a sequence of two courses in the freshman year, Fundamentals of Bioengineering I and II, whose purpose is to expose the students to the field of bioengineering as well as to introduce some important scientific, engineering and physiological topics which help lay the foundation for later courses. Laboratory experiences in the form of a Major Project are included in each course. The first semester course covers biomechanical, bioelectrical, instrumentation and computer topics; the second semester covers biochemical, metabolic, cellular, and integrative (e.g., biosensors) subject material. We decided to organize the first semester course around approximately 14 important physical and engineering laws and principles which are pertinent to biomechanics, bioelectricity and instrumentation. We chose this approach because we believe that the best foundation for further studies in biomedical engineering is formed when students learn and practice basic principles which underlie the field. The laws and principles we selected, and the order in which they are presented, are given in Table I. Table I Ð Laws and Principles Covered in the Course Units 1. DarcyÕs Law (membranes) 2. PoiseuilleÕs Law (flow through tubes) 3. HookeÕs Law (elasticity and compliance) 4. StarlingÕs Law (cardiac adjustment) 5. EulerÕs Method (finite-difference solutions) 6. Muscle, Force and Leverage 7. Work, Energy and Power 8. OhmÕs Law (current, voltage, resistance) 9. KirchhoffÕs Laws (circuit analysis) 10. Operational Amplifiers (gain, feedback) 11. CoulombÕs Law (capacitors, fluid analogs) 12. Thevenin Equivalent (1-order time constants) 13. Nernst Potential (cell membranes) 14. Fourier Series P ge 7.280.1 Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright © 2002, American Society for Engineering Education Written Unit Material Ð We found no textbook that presented the material quite in the form we desired, so we wrote a series of notes covering each topic. The level of the material assumes that the students are skilled in algebra, have had some physics and chemistry in high school, and are concurrently enrolled in a Calculus I (or higher) course. This is appropriate for nearly all of our incoming freshman class. After being used for a couple of years, the notes have evolved into a complete set of Òunits,Ó one for each topic in Table I, and each taking about a week to cover in the lecture portion of the class. Homework sets are assigned with each unit, and when homework and examples are included, the units are about at the stage of a standard textbook. The Major Project: Modeling the Cardiovascular System Ð To tie many (about 80%) of the courseÕs topics together and to give the students some handson experience with the principles, a semester-long Major Project is assigned which models the human systemic cardiovascular (CV) system. During the first half of the semester, the students individually do computer modeling of the pressure waveforms around the systemic loop; then during the second half, in teams of two, they assemble and measure an electrical circuit simulating the same system, as discussed in more detail below. Following an explanation of the role that approximations play in engineering modeling, a common model diagram, shown in Fig. 1, is given to all the students. The assigned project models only the systemic portion of the system, ignoring the pulmonary circuit, and represents the left heart by only a single chamberÑthe ventricle (including both the mitral and aortic valves). The systemic CV loop is broken into five segments, each with compliance and resistance values which each student calculates using physiological tables and graphs that are provided.