Alice R. Villalobos, BS, PhD
Texas Tech University
As teachers we hope students remember and apply all the physiology they learned in our class. However, many undergraduate students hope simply to get through this semester of physiology and their other courses. They dread the amount of material and that ‘so many things go on in the body at one time.’ I asked myself what could be integrated into lecture or lab to help students better learn material in class, study more effectively on their own and ideally, improve recall when taking exams. Around this time, I attended a teaching workshop focused on short activities and simple tools that could be incorporated into lectures to facilitate learning and recall. One tool was the ‘bumper sticker’.
Similar to an actual bumper sticker, the teaching bumper sticker is a short memorable phrase or slogan that encapsulates a thought, principle, or concept. In this case, a bumper sticker helps students learn and remember a concept or principle. In all areas of life, we use short sayings or one-liners often of unknown derivation that convey a profound or funny, classic or clever, instructional or encouraging thought. ‘Righty tighty, lefty loosey.’ means turn the screw to right to tighten and left to loosen. “I before E except after C.” with the addendum, “… and in words, such as protein or weight.” Could bumper stickers work in a physiology course? I already borrowed “Water follows sodium; sodium doesn’t follow water.” from my undergraduate professor. We all develop short phrases while working on lectures, reading physiology papers and books, or on the fly during lecture.
Recently, I began using bumper stickers in a more organized manner. I took a sheet of lined paper, wrote ‘Bumper Stickers for A&P-II’ on the top, and made plenty of copies. On the first day of class I discussed tips to improve learning and study habits. I explained the bumper sticker was a teaching/learning tool and gave each student a sheet. I admitted it was an experiment, but my intention was to give them short phrases to refer to and contemplate when studying on their own or spark a memory on an exam. That very day we started glycolysis. The first bumper sticker was “You must spend an ATP to make ATP.” I explained the first step in glycolysis is phosphorylation, using a phosphate from ATP. Despite some initial skepticism, bumper stickers caught on and helped many students.
Rather than repeating your explanation verbatim, students must accurately explain concepts to themselves and others in their own words. When students study with a partner or in groups, they can refer back to the bumper sticker along with lecture notes, diagrams and textbook to explain the respective concept to each other in their own words and peer-correct. When students are teaching each other, they are truly ‘getting it’. Granted, it is essential that students use more exact and scientific vocabulary to describe a mechanism or concept, as is true for any discipline. For most students this won’t happen the very first time they explain the concept. Learning physiology or any subject is a process; developing the vocabulary is part of that process. A memorable bumper sticker is a prompt for stimulating discussion – verbal communication in the context of learning a given physiological mechanism and developing the vocabulary of physiology.
There is no established technique for the initial delivery of a bumper sticker phrase. However, its two-fold purpose as a teaching/learning tool is to help students understand and remember a concept; thus, the phrase and initial proclamation must be memorable. Based on my hits and misses, here are several tips. First, keep it short, ideally 10 words or less. Second, timing is key. Similar to a joke, timing is important but varies with topic and teaching style. Some use the phrase as a teaser to introduce a topic; others use it to summarize key points. Third, be as direct as possible and capture students’ full attention. Some write the phrase on the board or slide and make an announcement, “Listen up. Write this down.” Fourth, look directly at your students and state the phrase clearly with meaning, effective voice inflection, dramatic tone, appropriate pause, facial expression, hand gesturing, and/or a little physical comedy. Fifth, use accurate and scientific terms to explain the meaning of the phrase as it applies to the physiological concept. This is absolutely critical. Left to interpretation, students might misunderstand the actual physiological concept.
Bumper stickers for better study and testing strategies
*Use common sense at all times, especially on test day.* At times, students forget obvious and intuitive things. For example, when applying Boyle’s Law to respiration, don’t forget to breathe. I remind students that lung volume and intrapulmonary pressure will change such that when we inhale air flows in, and when we exhale air flows out. Physical laws applied to physiological mechanisms explain relationships among different components of a mechanism, e.g., the pressure of a quantity of gas to its volume. I assure them, they can and will learn the fundamental physics on which Boyle’s law is based, but keep it simple and remember – when you inhale air flows in, when you exhale air flows out.
*Understand the question, before you answer it.* My PhD advisor shared this pearl of wisdom before my qualifying exam. I encourage students to calmly, slowly and deliberately read the entire question. On any multiple choice or essay exam, they must be certain of what is being asked, before answering a question. Do not stop reading the question until you come to a period, question mark or exclamation point. Students are concerned about wasting precious time. Slowing down just a bit to answer correctly is worth the time and decreases the odds of second guessing or having to go back to the question. I make another pitch for reading the text book. It is a way to practice reading calmly and deliberately and catching differences in font or formatting, e.g., print style, italics, bold, underline, that may indicate key terms for an exam question.
Bumper stickers for general principles in physiology
*Enough, but not too much.* Many students think every physiological end point is maintained at a constant value. I explain that various parameters are regulated such that they gently fluctuate within a narrow range. Plasma sodium must be ‘enough’; if it drops too low osmolarity decreases. If sodium is ‘too much’, osmolarity increases; plasma volume increases; blood pressure increases. If an endpoint falls below range, regulatory mechanisms bring it back up into range; should it increase above normal range, regulatory mechanisms bring it back down into range.
*It’s not a mathematical equation; it’s a relationship.* Many students confess they are ‘really bad at math’ or ‘hate math’. CO, MAP, renal clearance, alveolar ventilation rate – all math. Understanding and passing physiology requires math. I tell students math describes physiological relationships between different factors that regulate or dictate a given endpoint, similar to interactions and relationships among friends or a team. Actual equations represent precise relationships, e.g., CO = HR x SV. In that case, cardiac output will increase and decrease in direct proportion to heart rate and stroke volume. Then there is Poiseuille’s Equation. Students are not required to memorize that equation, but they must learn and apply the principles of the equation: F α DP, F α 1/R and F α r4. I clarify the α symbol means ‘in proportion to’, not equals. I repeat, ‘It’s not a mathematical equation; it’s a relationship.” I suggest they view a as a hug, and embrace the dependence of blood flow on the pressure gradient, vascular resistance, and the luminal radius. The 4 means when radius changes even just a little, flow changes a lot! I provide a more technical explanation of how blood flow can decrease significantly with gentle vasoconstriction and increase with gentle vasodilation; this showcases the essential regulatory role of vascular smooth muscle. This particular bumper sticker serves to remind them math is critical to our understanding of physiology and hopefully, ease their anxiety. More math awaits in respiratory physiology, and they revisit and apply F α DP, F α 1/R and F α r4 to air flow.
*Know what abbreviations mean, and don’t make up abbreviations.* I explain the names of hormones, especially, are rich in information. These names indicate source, stimulus for release, and mechanism of action. For example, atrial natriuretic peptide, ANP, is a peptide hormone secreted from atrial tissue when plasma volume increases that increases urine output (-uretic) and sodium (natri-) excretion. Not too creative, but self-explanatory. Couple it with “Water follows sodium …”; problem solved.
Bumper stickers for chronological order or sequence
For many cellular and organ mechanisms, there is a strict chronological order of events. During the cardiac cycle, there is a distinct chronological order for each of several different phenomena that occur simultaneously and interdependently. I use bumper stickers to teach a basic concept of cardiac physiology that help students learn the cardiac cycle – the electrical~mechanical relationship. First, I show the entire Wiggers diagram and explain it tracks the series of interrelated electrical and mechanical events as they occur in the same timeline of one heartbeat. I assure them we will take one panel at a time and pull it altogether at the end. I start with the relationship of the ECG to the 4 ventricular phases, using a set of bumper sticker phrases that I write on the board. We review the electrical events of P (atrial depolarization), QRS (ventricular depolarization) and T (ventricular repolarization) deflections. Then, I say, “Pay attention. Write down each phrase.”
*Electrical then mechanical.* I explain emphatically that first an electrical signal is transmitted and received, then the atrial or ventricular muscle responds. In the cardiac cycle, electrical events P, QRS, and T each precede atrial or ventricular responses.
*Depolarizeàcontract. Repolarizeàrelax.* I explain depolarization triggers contraction; repolarization leads to relaxation. P wave signals atrial contraction; QRS complex signals ventricular contraction; T wave signals ventricular relaxation.
*Depolarizeàcontractàincrease pressure. Repolarizeàrelaxàdecrease pressure.* I remind them changes in pressure gradients across the atrioventricular and semilunar valves determine whether valves open or close and consequently, whether blood flows into or out of the ventricle. Depolarization leads to ventricular contraction and in turn, an increase in pressure; repolarization leads to ventricular relaxation and in turn, a decrease in pressure.
*The AV valve is the fill valve; the semilunar valve is the ejection valve.* A student thought of this phrase! She explained, “When the AV valve – tricuspid or mitral – is open during diastole, the ventricle fills with blood from the atrium. When the semilunar valve – pulmonary or aortic – is open during systole, blood is ejected.” In that moment I thought my work as a teacher was done; my student is teaching herself and others. I give her full credit, but use her bumper sticker. I further explain when the ventricle relaxes and pressure drops below the atrial pressure, the AV valve will open, and blood enters the ventricle; when it contracts ventricular pressure exceeds atrial pressure and the AV valve closes; as it continues to contract, eventually ventricular pressure exceeds aortic pressure, the aortic valves opens, and blood is ejected into the aorta.
Bumper stickers might not be the right tool for every teacher, student, or topic, or be appropriate for undergraduate versus graduate course. If you decide to implement this tool, you might not have a bumper sticker for every basic or general physiology concept or mechanism or a set of bumper stickers for every organ system. You might only use a bumper sticker phrase once or twice in a whole semester. When used appropriately, they truly can make a difference. On the other hand – if how you teach is working just fine and your students are getting it – then all I have to say is, “If it ain’t broke, don’t fix it!”
Alice Villalobos received her Bachelors of Science in biology from Loyola Marymount University and her PhD in comparative physiology from the University of Arizona-College of Medicine. For the past several years, she has taught Anatomy & Physiology-II and Introduction to Human Nutrition in the Department of Biology at Blinn College and guest lectured at Texas A&M University on the topics of brain barrier physiology and heavy metal toxicology. She recently relocated to Texas Tech University to join the Department of Kinesiology & Sport Management where she teaches Physiological Nutrition for Exercise.