“Quantitative Physiology” has been one of the defining biomedical engineering courses at the McKelvey School of Engineering at Washington University in St. Louis for decades.

The course sequence consists of “Quantitative Physiology I” and “Quantitative Physiology II” and is considered by many to be the most difficult set of courses in the biomedical engineering curriculum. Better known collectively as “QP,” students learn to build and design ways to measure or observe human physiology. It requires students to apply previously learned principles of math, physics, chemistry, biology and computing, and understand how humans breathe, sense, move and experience their world.

“Almost everything we do in lab is a new, interesting and exciting challenge for the students,” said Patricia Widder, principal lecturer of biomedical engineering and associate director of undergraduate studies. “QP is a series of ‘ah ha’ moments for students seeing how things work in an engineering sense. We are synthesizing all these topic areas, chemistry, physics, biology, to be simultaneously applied. They learn to ask themselves, ‘what are my assumptions and what can I use?’”

Since its creation at the founding of the BME department in 1994, QP is where BME students get hands-on experience with electrode recordings of the visual cortex, active contractions of the beating heart or force transducers in deforming bone. Through QP, students develop fundamental knowledge of neurophysiology and cardiac electrophysiology and learn how engineers have developed devices and systems to monitor and decode the complexities of human physiology. No matter students’ post-baccalaureate plans, QP aims to set them up for success.

The course is taught by a rotation of faculty who present different modules.

In the first portion of the course, Quantitative Physiology I, Dennis Barbour, MD, PhD, professor of biomedical engineering and director of master’s studies, leads learning in neurophysiology, with students measuring their own brain waves in the associated labs. Jonathan Silva, professor of biomedical engineering, presents modules on bioelectricity in neurons and myocytes, showing students how to build theoretical models of electrically excitable cells such as muscles and neurons.

“Whether their ultimate goal is industry, entrepreneurship, research or medicine, the knowledge learned in QP will prepare them,” Widder said.

In the thick of it

Ahmed Ahmed, who is majoring in biomedical engineering, and George Mitrev, who is majoring in biomedical engineering and systems science & engineering, took the course sequence during the 2022-23 academic year. They said even first-year biomedical engineering students are aware of QP’s reputation.

“Starting with ‘Introduction to BME,’ there’s this notion that we’re preparing for QP,” Ahmed said. “Especially in ‘Biomechanics,’ when we start doing longer lab reports and focusing on how to analyze our data.”

While neither Ahmed nor Mitrev said they found the material intimidating, they both admitted that managing such a work-intensive course was a challenge. Each week, students complete labs that vary from tissue dissection and organ isolation to building electrocardiograms from scratch. They must complete an in-depth report following each lab.

“It’s a rewarding experience because you realize the tools to create the medical devices of tomorrow aren’t out of reach for us,” Mitrev said. “The university provides extraordinary equipment and instructors. You don’t need $100,000 to build a medical device, and you definitely don’t need $100,000 to learn about building a medical device.”

Through the years

Since the QP course was created, it has grown to meet the needs of students while staying current with changing trends and technology.

While neural and cardiac physiology have remained a staple of QP allowing students to learn the principles of electrocardiography, electromyography and electroencephalography, new disciplines are frequently added to the course. With the expansion of tools in molecular biology and systems engineering, QP brought lessons in systems biology, building computational networks to mimic drug-receptor interactions that affect muscle contractility. With advances in microfluidic systems that allow studies of gas-fluid exchange, QP introduced modules in respiratory physiology to understand how oxygen is transported from the lungs to the blood circulation.

Most recently, Christine O’Brien, assistant professor of biomedical engineering, has introduced physiology of reproduction and women’s health, central to her own research. In one of these modules, students perform peripheral blood flow measurements using a light-based imaging technique and learn how peripheral blood flow decreases during postpartum hemorrhage, the global leading cause of maternal mortality. Students first measured a tissue-mimicking blood flow phantom across a range of flow rates, and then measured their own blood flow during multiple physiology challenges, such as occluding blood flow or placing their hands in cold water.

To tackle the important contributions of engineers to imaging systems design and measures, Chao Zhou, professor of biomedical engineering, introduced a module that shows students a range of imaging techniques such as CT, MRI, PET, ultrasound and optical imaging methods. In labs, students use brightfield and fluorescence microscopes to observe and measure cell structures and optical coherence tomography (OCT) imaging on fruit fly models to study intricate cardiac physiology parameters, such as heart rate and chamber dimensions.

This focus on imaging systems has resulted in more biomedical engineering students choosing to continue on to earn graduate degrees in imaging science.

A lasting impression

This course continues to resonate with students and alumni alike with its impact extending far beyond the classroom. Even decades after taking the class, former students recall the profound influence it had on their academic and professional journeys.

Alumni, regardless of their career paths in research, industry or medicine, carry with them the knowledge and experiences acquired through QP.

Krista Gietl, head of digital and ecommerce analytics at MilliporeSigma, earned a bachelor’s degree from WashU in 2013.

Despite its challenges, Gietl said she enjoyed the experiments and that the class helped her build confidence. “I think that’s the cool thing about the class, too, is that you’re doing most of these experiments on yourself, so everyone’s signals look a little different,” Gietl said. “I liked the last lab when you have to design the experiment yourself. We did one on cardiac output and lung volume. One of my lab partners was a semiprofessional cyclist, so we brought in his bike equipment that we could hook up to measure things from his body and made a lab about it. That was fun and showed you you’ve done this enough that you can design an experiment and write a 15-page report about it.”

Likewise, Helen Blake, MD, who earned a bachelor’s degree from WashU in 2003 and is an interventional pain physician in St. Louis, cites QP as a formative experience during her path to medical school.

“In the lab component, we could actually watch the theories and everything that we were learning about in practice,” Blake said. “We electrically stimulated frog muscles and watched the contractions and the action potentials, measured the sodium gradients and really learned specifically how nerves work to contract muscles. I remember doing a lab where we hooked ourselves up to cardiac monitors, and we actually massaged our own vagal nerves and watched the impact that it had on our heart rate. When I was studying that same phenomenon in medical school and how your heart rate can change with pressure on the vagus nerve or with respiration, it was like an anchor point to be able to really have seen that in real-time in a laboratory setting.”

Beyond QP, Blake says that her engineering education has shaped her professionally.

“I didn’t know how my engineering background would impact my actual formal career,” Blake said. “I knew I wanted to be a doctor, but so many things did have applicability to both medical school as well as what I do now in interventional pain. There are probably so many subtle ways that the knowledge that I gained during college and during those classes has influenced my ability to understand and apply my own specialty.”

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