“The Wave” – Neuron Action Potential Propagation

Some of our most popular blog posts describe teaching tips developed by HAPS members. We choose a handful of these to publish on the blog, but there are hundreds of tips that have been collected over the years. These little snippets are being linked to the HAPS A&P learning outcomes and posted to the HAPS website, for members only. So join HAPS now, and get access to many more teaching tips like this one.

Enjoy this teaching tip from HAPS Past President, Terry Thompson.

Objectives:

  1. Engage students with a kinesthetic demonstration of the action potential “wave” with ions moving in or out of membrane channels
  2. Generate visual memory tools to help students’ learning and long-term understanding
  3. Motivate critical thinking by having students analyze and evaluate various components of the activity as a model of the physiological events

Materials:

  • Color-coded cards: multiple cards with Na+/K+ on opposite sides; one card with ACh/Ca2+ on opposite sides; one card with neuron cell body/synaptic end bulb on opposite sides. Can use cardstock or plastic protective sleeves. Use large font to fill single page.

 Procedure:

  1. Line students up facing class (or each other if using two lines). Explain that students will represent the axolemma: phosphate “head”, lipid “legs”, voltage-gated channels “arms”.
  2. Give each student a Na+/K+ card and review relative concentration of each ion extracellular and intracellular. Designate: above “heads” as extracellular and floor as intracellular; right hand as voltage-gated Na+ channel and left hand as voltage-gated K+ channel. Start with Na+ card held toward observers, above their heads, in right hand.
  3. Demonstrate the depolarization/repolarization cycle by bringing Na+ card down in front of body, flipping K+ side toward observers as pass to left hand, then move above head.  Have all the students practice this synchronously until they feel comfortable, saying “depolarize” and “repolarize” out loud to help.  Discuss the electrogenic activity of the Na+/K+-ATPase pump as it relates to this kinesthetic demonstration.
  4. Review continuous conduction and challenge them to now complete the same movements but this time in sequence, like the “wave” in a stadium.  Show the “neuron cell body” and “ACh” cards and discuss what initiates the impulse.  Can elaborate on difference between ligand-gated and voltage-gated channels; graded potential, threshold, and action potential; neurotransmitter for motor neuron or other neurons; dendrites, soma and axon hillock; etc.  Students will often come up with ideas of ways you could include other elements in the demonstration, or at least evaluate and understand what this particular activity as a model is NOT showing.
  5. “Start” the first person in line by saying “threshold”, and allow the “wave” to progress down the axon.  This usually elicits lots of laughing and suggestions from the audience.  Allow them to repeat until they produce a reasonable “wave”, starting each with a threshold stimulus.
  6. Finally as a reasonable “wave” is progressing down the line, run to the other end and flip your cards to show synaptic end bulb and hold the Ca2+ card above your head.  When the wave reaches you, bring the Ca2+ down and flip to ACh, passing it above your head for release of neurotransmitter at synapse with muscle or another neuron.  Discuss this added activity to the model as a way to summarize the activity.
  7. Extensions can include discussing what parts of this demonstration could be improved on or don’t accurately reflect the physiology.  Can also discuss what would need to be changed to demonstrate saltatory conduction instead of continuous conduction.

NOTE: This activity was also presented by Terry Thompson at 2016 HAPS Atlanta Conference as part of the group workshop entitled “Add Drama to Your Classroom – Great Kinesthetic Activities for Students.”

Quick analogy for subclavian artery name changes

Although it is not a particularly difficult concept, sometimes students have trouble remembering the different names that the subclavian artery takes on as it passes through the superior mediastinum and base of the neck into the axilla (as the axillary artery) and arm (as the brachial artery), or they don’t quite get that it is the same vessel with three different names.

Every one of my students has to drive along these roads to get to school.
Every one of my students has to drive along these roads to get to school.

One thing I do in lecture and lab is to analogize this name change using name changes for streets in town. Fortunately, I work at a university (Benedictine University in Lisle, IL) that is situated on a road (College Road) that changes name to the north (Yackley Avenue) and to the south (Wehrli Road) without changing direction appreciably. Every student has to drive along these roads to get to school. I tell my students that the subclavian artery is like Yackley Avenue, and when it crosses the lateral edge of the first rib (in this analogy, Maple Avenue, see Figure), it changes name to the axillary artery (College Avenue); it changes name again after crossing the inferior margin of the teres major muscle (Hobson Road, see Figure), at which point it becomes the brachial artery (Wehrli Road). I would wager that many (most?) towns in the United States have roads that change names in the same way, so that the analogy could be adapted to local conditions. A particularly good example, in Washington, DC, is Constitution Avenue, which starts as I-66E, changes to US-50E/Constitution Avenue after crossing Roosevelt Bridge, and then turns into Maryland Avenue after crossing 2nd Street NE.

Of course, every semester the students and I question the sanity of anatomists and city planners alike for changing a perfectly good name again and again. I wonder how many students, driving home from my anatomy class, are thinking about the different names for the main artery of the upper limb as they drive along Yackley Avenue/College Road/Wehrli Road?


Robert McCarthy is an assistant professor in the Department of Biological Sciences at Benedictine University in Lisle, IL, where he teaches human anatomy and evolution to undergraduate biology and health science students. Robert is a biological anthropologist who studies the evolution of speech and language, the primate skull, hominin evolution, and human anatomic variation.

RAAS – Glug Glug Glug…

When I teach endocrinology students our unit on the adrenal gland cortical hormones, I always post a PowerPoint slide which depicts a Wikipedia image of the renin-aldosterone-angiotensin-system (RAAS).

Renin-angiotensin-aldosterone_system
This image is licensed CC-BY-SA 3.0 by A. Rad. Accessed on 12/4/17.

Its author does an elegant job of elaborating angiotensin II’s targets and responses, which include increases in sympathetic nervous system activity, tubular Na+ reabsorption and K+ excretion and H2O retention, adrenal cortex release of aldosterone, arteriolar vasoconstriction with a concomitant increase in blood pressure, and posterior pituitary release of ADH (arginine vasopressin) leading to reabsorption of H2O by the collecting duct. Overall there is an increase in the perfusion of the juxtaglomerular apparatus (JGA), which offers the negative feedback signal to reduce renin output by the JGA.

I point out to students this elegant, multiple-organ defense of falling blood pressure: the kidney (for renin release), liver, lung, adrenal cortex, hypothalamus (for both CRH and ADH), and kidney (for elevated perfusion) is all automatic. But when I show diagrams from multiple sources, including texts, I offer this question, “What is missing from these images?” I do prompt them with a clue about loss of perspiration during  workouts, but the ‘lights don’t go on’ until I reveal a PowerPoint shape with this on it, “Glug, glug, glug” – then they smile …. because they realize that drinking fluids provides the fastest return from hypovolemia…

Be thorough. Connect the dots.


Post comes from Robert S. Rawding, Ph.D., Professor in the Department of Biology at Gannon University in Erie, PA.

“I Was Too Embarrassed”

Exploring the Reasons Students Don’t Engage with Instructors to Improve Performance

“I was too embarrassed. He would think I was stupid,” replied my private tutoring client. This was her only response to why she did not meet with her professor after failing every exam the first time she took A&P 2 at a nearby university. I told her that most professors I know don’t assume that you are unintelligent if you’re struggling to understand material. The startling part of this exchange was her response to my reassurance, which was to ask, “Really?” She was genuinely surprised to hear that he would not assume she was an incapable student.

I didn’t think too much about this again until I picked up another student who also failed A&P 2 at a nearby community college. The story was the same, with a few added details. Despite failing 4 exams, no attempt was made to meet with the professor to discuss strategies for improvement. I asked her why. “Probably because I was embarrassed I did so poorly. I didn’t want to face my professor. Also, I didn’t think it would be helpful to go back and look, because reading the correct answers doesn’t really help matters if you don’t understand the content to begin with, so why make myself look stupid?” Now my curiosity was peaked. Is this how most students who don’t want to review and discuss their performance feel? Do they assume that they will either be judged, or that there’s nothing to be learned from seeing their mistakes? This might be especially true when exams are not cumulative. They may assume it’s better to just move on, in which case they are likely to repeat the same mistakes in preparing for the next assessment. It is easy to assume that only the students who are struggling will make appointments to review their performance, but from my experience, t’s usually the students hitting close to the average that view their exams, and the high and low scoring cohorts stay silent. The question then remains: Why would embarrassment stop a student from discussing their performance? Wouldn’t the desire to avoid more failure, or repeating a course, outweigh the risk?

Let’s assume for simplicity’s sake that you have created a supportive environment, you make yourself available, and when students do come, you provide constructive feedback that leaves them more confident and better prepared moving forward. However, the students who are struggling still don’t reach out. What else can, or should, an instructor do, for a student afraid of judgment? It is all too easy to write this off as a “silly” emotion, especially if you are a friendly, enthusiastic instructor (and I’ve never met a HAPSter who wasn’t!). However, after my experiences with the tutoring students over the summer, I decided to change up the language I used when I invited exams this academic year. I stressed the importance of failure in success.  I shared stories of my own academic struggles with students, stressing that some topics came naturally, and others were very hard to grasp, and took many hours of self-study outside the classroom to finally take hold. Finally, and what I feel made the biggest difference, I added the simple statement “please do not feel embarrassed to meet with me and review your exam” to my class email. The result? The number of my A&P students who came to review their midterms this year tripled from the five previous years.

For students, it does not always go without saying that we won’t judge their intelligence or ability. Say it. It takes almost no time, but you may see it make a big difference in the number of students who reach out for help. Do the easy things to get them in the door, and they may leave more self-directed, confident students. It may be hard for those of us who work in education to imagine letting embarrassment prevent us from getting better grades, but I’m sure that if we were all honest with ourselves, we could identify something we avoid because of fear of judgement. Students ultimately have to help themselves, but we can certainly help them get out of their own way.


Dr. Krista Rompolski is an Assistant Teaching Professor at Drexel University. 

Action Potentials can be a Puzzle

I found myself digging through a closet of scrap-booking goods last night in a frantic effort to find a 1 3/8” hole punch. I had been sparked by an idea that has been percolating for years, but I’ve never implemented. I wanted to build a cell with ions, channels, and charges so my students could manipulate the “players” involved in the resting membrane potential and an action potential.

This concept is particularly challenging for students. They could use chemistry, biology, and elements of physics to understand this system, but mine are woefully under prepared. Their eyes glaze over when they have to think about electrical gradients and chemical gradients working simultaneously. Add in channel types and applications to graphs that describe membrane changes in voltage, and even I’m starting to have an anxiety attack! When I teach this concept, the energy in my classroom is so thick, I could cut it with a knife. There has to be a better way.

berfore-ap
Before…

But so far, no amount of restructuring, dividing, or attempting to present just a “snapshot” in time had worked to facilitate the connection between what is occurring with ions and how it happens. So I cut out a giant cell, a little positive and negative sign, and all the different channels, and put them in a bag. That handy scrapbook punch allowed me to make sets of 10 potassium ions and 10 sodium ions in the colors I have been trying to get my students to associate with this concept. Voila- my students will now have an intracellular space on a table that represents the extracellular space…and all the important pieces as well.

before-ap
…and after.

Back in the classroom, as I drew on the board a picture of each step of the electrical changes experienced by the cell, they had to manipulate their cell. Did it work dreamily well? Probably not. Some students got it and visibly relaxed. But some students didn’t get it…and remained in a state of panic. However, I did discover that my students were pretty mixed up by the concepts of “depolarization” and “repolarization.” Because they can’t see the cell, sometimes this creates a mental block.

After class, a subset of students followed me to my office, where we played more with the model and I’ll be darned if they didn’t get to the point where they could set up their cell appropriately for each of the phases of the action potential! I could ask questions like, “Can the cell be stimulated again at this point?” And the question I love more, “WHY!?!” Light bulbs started turning on and several students took pictures so they could make their own model at home to use while studying.

This week in lab we use the HHsim program to study action potentials and this time, my new models will be on the table with them and they are going to have to show me what happens to explain the graphical results they get. My hope is that time, coupled with this paper model, will help them master the concepts.


Nichole Warwick teaches biology at Clatsop Community College and is a proud member of the HAPS Communications Committee.

Learning – Always in Style

Take Rational Course Design with Margaret Weck!
A message from HAPS President Emeritus, Margaret Weck!

Have you ever noticed how variable the depth of learning is amongst students in your classroom – even when you have students with very similar backgrounds and levels of preparation?  Perhaps you’ve looked for patterns or specific characteristics that might help explain this variability.  After all, if you can find consistent and predictable behavioral patterns, you might discover the key to motivating and assisting those who are struggling with coursework.  One useful tool for doing just that is to identify each student’s preferred “learning style,” a method that groups students based on their preferred means of learning.  Interestingly, this very topic was the focus of a HAPS –L discussion forum this past summer.   Following is a brief summary of the main points of that discussion supplemented with a little additional information.

A 2004 book by Coffield, et al. (1) identified 71 different learning style models, most of which are variations of two particular general themes. One of these themes is psychologically-oriented and looks at how individuals make sense of their personal experiences.  Examples include David Kolb’s Learning Styles Inventory (LSI) and Zubin Austin’s Health Professionals Inventory of Learning Styles (H-PILS).  The second major theme focuses more on neurological sensory information processing.  Examples include the right-brain vs. left-brain dominance tests and Neil Fleming’s Visual, Aural, Read/Write, Kinesthetic (VARK) inventory, a tool that indicates a person’s preferences for sensory modalities that most smoothly facilitate the mastering of new information.  

Will I be able to definitively resolve the central issues of learning styles in this post?  Of course not.  As we all know, it is notoriously difficult to “prove” anything, even without the additional handicap of measuring psychological processes through self-report.  In my opinion, it’s not worth the necessary paper or electrons to engage in a heated debate over this, especially since the take-home message is pretty much the same regardless of the outcome.  

Even those who strongly advocate the use of learning styles are aware of the limitations of each specific model and the instruments used to categorize individual learners.  Furthermore, the results of every inventory are full of questions of validity, reliability, and stability.  In other words, what does it really mean for someone to be an “assimilator,” or a “kinesthetic learner,” or “right brained?”  Are people with one tendency actually incapable of learning in any other way? Are these tendencies fixed, or can one improve or broaden native capabilities or preferences with enough effort and exposure to new types of learning?  The questions are endless, and addressing them is beyond the scope of this article; however, Edutopia (2015) has an overview of the various opinions and positions held by education leaders on learning styles: http://www.edutopia.org/article/learning-styles-real-and-useful-todd-finley.  

Since 2008 (2) rigorous educational research has not shown that specific instruction targeted toward a student’s learning style produces any statistically significant improvement in measured learning as compared to a non-preferred learning style.  Yet the debate over the usefulness/uselessness of learning styles persists.  

As far as course design is concerned, “universal” instructional design already encourages the use of multiple delivery modes to both present and assess student understanding of the most important ideas in our content.  Using multiple forms of representing and expressing key information automatically helps students find at least one point of entry into the content. So if preferred learning styles are real facilitators of learning, universal design already addresses them to a large degree.  Additionally, multiple presentation and assessment modalities provide reinforcement and a variety of possible retrieval cues which should help everyone – regardless of learning style.

One big positive offered by learning styles is that they are a non-threatening way to engage students in conversations about their learning.  Many students do not routinely participate in systematic self-reflection, but we can encourage them to talk about how they learn and what it means to demonstrate their own understanding of a subject by using easy-to-understand terminology found in the learning styles inventory.  As long as we don’t affix permanent labels to our students, which in effect “excuses” them from mastering the material, learning styles can provide students with insight into their own learning and offer a source of concrete strategies for engaging with course material.

  1. Coffield, F., Moseley, d., Hall, E., & Ecclestone, K. (2004) Learning styles and pedagogy in post-16 Learning: A systematic and critical review. London: Learning and Skills Research Centre.
  2. Pashler, H., McDanierl, M., Rohrer,  D. & Bjork, R. (2008) Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest 9(3):105-119.

Do Our A&P Students Know How to Read? Part 3

valerie-lee
A message from Valerie Lee, an assistant professor at Southern Adventist University who just started her 6th year of teaching and loves HAPS!

In Parts 1 and 2 of this blog series, we identified that Anatomy & Physiology students are having difficulty with reading comprehension.  More specifically, their struggles are not limited to understanding specific content; rather, they are struggling with general vocabulary comprehension.
(To view Part 1 &/or Part 2 of this series,  Click the Link(s):
“Do Our A&P Students Know How to Read
 -PART 1             -PART 2

For her Southern Scholars senior research project, Molly Theus, first year Doctor of Veterinary Medicine student at the University of Georgia in Athens,  attempted to seek insight into this problem by asking four questions:

  1. Does a positive correlation exist between cumulative GPA and vocabulary comprehension?
  2. Does a positive correlation exist between time spent reading for pleasure and vocabulary comprehension?
  3. Does a positive correlation exist between being read to as a child and vocabulary comprehension?
  4. Is there a link between a student’s major and vocabulary comprehension?

Molly chose six classes as candidates for investigation: General Biology II, Principles of Biology, Anatomy and Physiology II, Cell and Molecular Biology, Studies in Daniel, and Pathophysiology (Table 1). These classes were chosen to include one lower (n=42) and one upper division (n=31) biology-major class, one lower (n=43) and one upper division (n=32) nursing class, and one lower (n=27) and one upper division (n=20) general education class (total n=195). To assess personal reading habits and history, a questionnaire was distributed to all students in the six selected classes. To assess vocabulary comprehension, a twenty-question multiple choice vocabulary quiz was also distributed. In order to assure anonymity, informed consent and student information forms were assigned a unique three number code corresponding to each questionnaire.

Participants were given a two-week period of time in which to complete the questionnaires. Once the packets were collected, each informed consent document containing student names was separated from the rest of the forms so that quiz scores were kept anonymous. The names were needed to compile average GPAs and class-standing information for each participant. GPA and class-standing was then matched to quiz scores using the unique numerical codes. We made use of an ANCOVA linear model to analyze our data. The number of questions missed on the vocabulary assessment was the dependent variable and the independent variables are listed in Table 2. University GPA was rank-transformed to meet parametric assumptions. Analysis was performed using R version 3.3.0.

The preliminary result yielded three key results:

KEY RESULT 1: Students’ reading for pleasure had no statistical significance for predicting higher scores on the vocabulary quiz (Table 2). This was contrary to what we had hypothesized based on the literature.  

KEY RESULT 2: In our model, the amount of time parents spent reading to their child was a statistically significant predictor of scores on the vocabulary comprehension quiz. This relationship was consistent even when controlling for university GPA (F(3, 183) = 4.80, p = 0.003; Figure 1).

KEY RESULT 3: A higher cumulative university GPA was also a significant predictor for improved quiz scores (F(1, 183) = 20.39, p = <0.001; Figure 2).

Molly and I were surprised that reading for pleasure was not a statistically significant indicator of vocabulary comprehension. Molly suggests several possible interpretations:

    • Students choose reading materiel at or below their reading level.
    • If a student’s reading level is low, that might inhibit acquisition of non-content specific collegiate vocabulary.
    • Self reporting is not a precise tool.

What can we do with this information?

  • Early intervention seems to be key to the issue of vocabulary comprehension
  • Collegiate students identified as struggling with non-content specific vocabulary comprehension need interventions as well. Possible interventions include encouraging them to read challenging books outside of class and providing mentor support.
  • This is an interdisciplinary issue that needs to be addressed in every department.

The preliminary results are very interesting and both Molly and I are interested in collecting more data in the future by expanding the background questions asked and surveying both private and public institutions. If you are interested in helping us, contact me at vlee@southern.edu.