A Modular Approach to Teaching the Engineering Challenges of Physiology Gregory J. Sonek

1. A Modular Approach to Teaching the Engineering Challenges of Physiology Gregory J. Sonek Dept. of Electrical and Computer Engineering Merrimack College North Andover, MA ASEE New England Section 2006 Annual Conference, March 17-18, 2006

2. Background and Introduction • Course Structure and Development • Examples of Themes and Projects • Results and Conclusions ASEE New England Section 2006 Annual Conference, March 17-18, 2006

3. “Engineering Challenges in Physiology” is a course offered as part of a • biomedical engineering curriculum with the following goals and objectives: • To provide students with literacy and fluency in basic physiological • processes and systems • To enable students to identify, through an understanding of universal • concepts and themes, engineering challenges i.e. needs and opportunities • for new techniques, devices, and systems at the molecular, cellular, tissue, • and whole body scales • To provide an opportunity for application of course concepts through self • study and exploration Background and Introduction ASEE New England Section 2006 Annual Conference, March 17-18, 2006

4. Physiology is a highly interdisciplinary subject that crosses the boundaries of • science and engineering. Both the audience and course content present • significant challenges: • Course offered to undergraduates and graduates who are pursuing • BSBME degree, second major, and minor • ME, MS, and Ph.D. degrees • Certificate degree in bioengineering • Draws students that have diverse educational backgrounds and varying • degrees of industrial and professional training. Backgrounds include • Engineering (electrical, mechanical, chemical, biological) • Life sciences (biology, premedicine) • Physics • Students are motivated to leverage existing or prior experiences with • new coursework that will facilitate their involvement in the biomedical field Course Challenges ASEE New England Section 2006 Annual Conference, March 17-18, 2006

5. The subject of physiology is vast and diverse • Engineering concepts and themes must be reviewed and applied • Engineering challenges must be identified Course Challenges ASEE New England Section 2006 Annual Conference, March 17-18, 2006

6. A modular approach was adopted to address course challenges: • Present select topics in physiology in 2 – 3 week intensive modules • for in depth study • Develop common themes and concepts that bridge all systems • Use a combination of lectures, text readings, homework, and • weekly review of current events to engage all students • Draw upon expertise from faculty and researchers in specific • areas of physiology e.g. respiratory, neuro, cardiovascular, renal • Focus on problem solving, identification of problems, and challenges • Use a final project to integrate course concepts and provide an • opportunity for research and self exploration Course Structure and Development ASEE New England Section 2006 Annual Conference, March 17-18, 2006

7. Introduction to Engineering in Physiology • Human body as a complex system; sensing, feedback, and control • Physiological parameters, transport, fluid/gas mechanics, chemistry, electrical processes • Cellular Physiology • Cell structure, cell transport, ion channels • Potentials (membrane, action), intracellular signaling, neurotransmission • Neurophysiology • Central and peripheral nervous systems, autonomic and sympathetic processes • Receptors, neural pathways, sensory (auditory, visual) systems • Interfacing with the nervous system, neuro-prosthetics, bionic devices • Respiratory Physiology • Functional anatomy and control of breathing • Mechanics of breathing, gas exchange (diffusion), ventilation/perfusion matching • Cardiovascular Physiology • Basic hemodynamics, electrophysiology, electrocardiography • Mechanical events of the cardiac cycle, peripheral circulation regulation • Cardiac muscle mechanics, molecular cardiology • Renal Physiology • Quantitation of renal transport processes, renal tubular function • Acid/base balance, blood pressure and volume control • Special Topics • Temperature regulation. exercise, high-altitude, and hyperbaric physiologies • Final Projects • Student chosen projects in select areas of physiology ASEE New England Section 2006 Annual Conference, March 17-18, 2006

8. The course emphasizes many basic principles and themes common across all • physiological systems, including: • Energy Electrochemical potential, metabolism (ATP, glucose, FFA) • Communications Signaling, receptors, integrated pathways • Information Audition, vision, tactile sensing, neural processing • Feedback & Open/closed loop, negative/positive feedback, sensor • Control integration with chemical and neural systems • Transport Drift, diffusion, passive and active transport, fluids, • gases, ions, solutes • Processes Chemical, mechanical, and electrical processes Basic Principles and Common Themes ASEE New England Section 2006 Annual Conference, March 17-18, 2006

9. An example of two principles that applies to many different systems are those of Ohm’s Law , where resistancerepresents opposition to flow (y = z x R) and Potential Energy (storage) represents the capacity for accumulation (y = 1/C z dt) OHM’S LAWCAPACITY Electrical V = IR q = C V Mechanical F = v Rm x = F Cm Fluidic DP = Q Rf DV = DP Cf ThermalDq = Q Rt Q = Dq Ct ChemicalDf = Q Rc M = V Cc x F I Q DP = P1 – P2 DV F DP v f1 q1 f2 q2 q1 q2 Q Df = f1 - f2 Basic Principles and Common Themes ASEE New England Section 2006 Annual Conference, March 17-18, 2006

10. Universal Concepts and Themes BASIC CONTROL SYSTEM WITH NEGATIVE FEEDBACK CONTROL SYSTEM WITH NEGATIVE AND POSTIVE FEEDBACK ASEE New England Section 2006 Annual Conference, March 17-18, 2006

11. INTERVENTION Baroreceptor firing rate Arterial Pressure Increase Decrease Baroreceptor stretch Sympathetic Activity Parasympathetic Activity a1-adrenergic receptor activation b1-adrenergic receptor activation Muscarinic receptor activation Systemic vascular resistance Force of Contraction Heart Rate Stroke Volume Cardiac Output Cardiovascular Feedback and Control ASEE New England Section 2006 Annual Conference, March 17-18, 2006

12. STEPCHEMICAL & PHYSICAL PRINCIPLES Alveolar Ventilation Fluid mechanics of laminar and turbulent flows Pulmonary Gas Diffusion; Henry’s Law; Law of Mass Action Exchange Allosteric conformational effects on hemoglobin Oxygenated Blood Fluid mechanics; Physical chemistry of Circulation hemoglobin Extravascular Oxygen Diffusion Distribution Oxygen Transport into Diffusion; Henry’s Law; Mass Action Cells & Mitochrondria Cell Respiration Kinetics of electron transport chains Application of Engineering Principles EXAMPLE: OXYGEN CONSUMPTION ASEE New England Section 2006 Annual Conference, March 17-18, 2006

13. FIND RESISTANCE BY THE ISOVOLUME METHOD • IDENTIFY PATIENT P - V CURVES Analysis of Engineering and Clinical Data OBJECTIVE: To apply course engineering and physiological concepts to the solution of problems derived from real clinical or experimental data. EXAMPLE: To investigate the mechanics of breathing through the concepts of flow and pressure-flow relationships. Data is derived from spirometer and pneuno- tachograph measurements ASEE New England Section 2006 Annual Conference, March 17-18, 2006

14. Davenport Diagram • Henderson – Hasselbalch Eqn. • pH = pK + log [HCO3-] • 0.03 x PCO2 • pH = Kidneys • Lungs • Sample Conditions • A = Uncompensated metabolic acidosis • B = Metabolic alkalosis and respiratory • acidosis B A Analysis of Physiological Data EXAMPLE: To explore the role that the kidneys and lungs play in acid/base balance and identification of various acid/base disorders, including metabolic and respiratory acidosis and alkalosis ASEE New England Section 2006 Annual Conference, March 17-18, 2006

15. Engineering Concepts and Challenges • To further develop the theme of engineering challenges, modules use • take home assignments that pose open ended questions or problems for • which there are no current solutions. Some examples include: • Continuous Measurement of Airway Obstruction during Sleep • Requires a method for analyzing nasal flow and chest/abdomen movement • to diagnose hypopnea (reduction of airflow) in patients with obstructive sleep • apnea (OSA) • Implantable Gas Exchanger (Artificial Lung) as Lung Transplantation Alternative • Considers the design of an artificial gas exchanger as an alternative to extra- • corporeal oxygen devices for patients with advanced lung disease • Changes in Fluid Volumes and Osmolarities • Considers the changes to intracellular and extracellular fluid volumes and • osmolarities in marathon runners who compete on a hot day, rehydrate only with • pure water, and suffer muscle cramping near the end of a race ASEE New England Section 2006 Annual Conference, March 17-18, 2006

16. SUGGESTED TOPICSTUDENT PROJECTS Space Physiology“Physiological effects of fluid shifts on the cardiovascular system during space travel” Neonatal Physiology“Neurology and the human auditory system” “Effects of neutropenia in the neonate” “Respiratory physiology of preterm births” Sports Medicine Physiology“Turning Michael Johnson into a marathon runner” “Performance monitoring in cyclists: VO2 max, lactate threshold, nutrition, muscle function, and power training” High-Altitude Physiology“Engineering challenges in high-altitude physiology” Hyperbaric Medicine“Physiology under hyperbaric conditions” Final Projects ASEE New England Section 2006 Annual Conference, March 17-18, 2006

17. Examples “Performance Monitoring in Cyclists: VO2 max, lactate threshold, nutrition, muscle function, and power training” OBJECTIVE: To understand VO2 max and the factors that affect it, from basic metabolic processes and barriers, to muscle types, nutrition, training regimens, and devices used to monitor performance ASEE New England Section 2006 Annual Conference, March 17-18, 2006

18. Examples “Physiology under Hyperbaric Conditions” OBJECTIVE: To understand the effects of pressure on the human body, including Dalton’s Law, tissue saturation, nitrogen narcosis, and the neurological effects of gas partial pressures (lipid bilayer alteration, modified neuronal firing rates) ASEE New England Section 2006 Annual Conference, March 17-18, 2006

19. A modular approach to the study of engineering and its challenges in • physiology has proven to be a successful course model • The course focuses on concepts and themes that are common to • different physiological systems (cellular, neuro, respiratory, CV, renal) • It has the goal of helping students identify engineering challenges (needs • and opportunities) for new techniques, devices, and systems from the • molecular to whole body scales • The strength of the course lies in its breadth, interdisciplinary nature, • and expertise brought by a diverse group of faculty and lecturers with • backgrounds in engineering, medicine, R&D, and clinical applications Results and Conclusions ASEE New England Section 2006 Annual Conference, March 17-18, 2006

20. We are grateful to all the participating faculty, researchers, and students at Tufts University who made this work possible: Prof. David Kaplan Dept. of Biomedical Engineering Prof. Andrew Hoffman School of Veterinary Medicine and Lung Function Testing Laboratory Prof. Larry Engelking Dept. of Biomedical Sciences and School of Veterinary Medicine Prof. Eunice Bloomquist Dept. of Physiology and School of Medicine Dr. Michael Mendelsohn Molecular Cardiology Institute and NEMC Dr. Ron Risso Inner Sea Tech BME Students Brian Orrick, Jason Waterman, Clemens Alt, Leonardo Angelone Acknowledgments ASEE New England Section 2006 Annual Conference, March 17-18, 2006