William Cliff

Chemistry misconceptions associated with understanding calcium and phosphate homeostasis

Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration when calcium ions were added to a saturated calcium phosphate solution. Fifty-two percent of the students correctly predicted that the phosphate concentration would decrease in accord with the common ion effect. Forty-two percent of the students predicted that the phosphate concentration would not change. Written explanations showed that most students failed to evoke the idea of competing chemical equilibria. A second question assessed the predicted change in calcium concentration after solid calcium phosphate was added to a saturated solution. Only 11% of the students correctly predicted no change in calcium concentration; 86% of the students predicted an increase, and many based their prediction on a mistaken application of Le Chateliers principle to heterogeneous equilibria. These results indicate that many students possess misconceptions about chemical equilibrium that may hamper understanding of the processes of calcium and phosphate homeostasis. Instructors can help students gain greater understanding of these physiochemical phenomena by adopting strategies that enable students achieve more accurate conceptions of chemical equilibria.

A conceptual framework for homeostasis: development and validation

We have developed and validated a conceptual framework for understanding and teaching organismal homeostasis at the undergraduate level. The resulting homeostasis conceptual framework details critical components and constituent ideas underlying the concept of homeostasis. It has been validated by a broad range of physiology faculty members from community colleges, primarily undergraduate institutions, research universities, and medical schools. In online surveys, faculty members confirmed the relevance of each item in the framework for undergraduate physiology and rated the importance and difficulty of each. The homeostasis conceptual framework was constructed as a guide for teaching and learning of this critical core concept in physiology, and it also paves the way for the development of a concept inventory for homeostasis.

Development and Validation of the Homeostasis Concept Inventory

The Homeostasis Concept Inventory (HCI) is a 20-item multiple-choice instrument that assesses how undergraduates understand homeostasis. The authors explain how they developed the HCI and collected evidence about its validity and reliability. The process included seeking feedback from students and instructors at all types of undergraduate institutions.

How the story unfolds: exploring ways faculty develop open-ended and closed-ended case designs

Open-ended or closed-ended case study design schemes offer different educational advantages. Anatomy and physiology faculty members who participated in a conference workshop were given an identical case about blood doping and asked to build either an open-ended study or a closed-ended study. The workshop participants created a rich array of case questions. Participant-written learning objectives and case questions were compared, and the questions were examined to determine whether they satisfied criteria for open or closed endedness. Many of the participant-written learning objectives were not well matched with the case questions, and participants had differing success writing suitable case questions. Workshop participants were more successful in creating closed-ended questions than open-ended ones. Eighty-eight percent of the questions produced by participants assigned to write closed-ended questions were considered closed ended, whereas only 43% of the questions produced by participants assigned to write open-ended questions were deemed open ended. Our findings indicate that, despite the fact that instructors of anatomy and physiology recognize the value of open-ended questions, they have greater difficulty in creating them. We conclude that faculty should pay careful attention to learning outcomes as they craft open-ended case questions if they wish to ensure that students are prompted to use and improve their higher-order thinking skills.

What Is the New Paradigm and What Is New About It

With the publication of Thomas Kuhn’s The Structure of Scientific Revolutions in 1962, the term “paradigm” took on several specialized meanings. It is our contention that the changes to physiology education that we are recommending constitute a new paradigm in the Kuhnian sense.

What Are the Core Concepts of Physiology

What are the core concepts of physiology? Michael et al. (Adv Physiol Educ 33:10–16, 2009) defined nine core concepts in physiology. As a result of surveying physiology faculty at a wide variety of institutions in the USA and elsewhere, Michael and McFarland (Adv Physiol Educ 35:336–341, 2011) expanded this list to a set of 15 core concepts for physiology.

The “Unpacked” Core Concept of Homeostasis

We define homeostasis to be the maintenance of a constant internal environment by active functioning of cells, tissues, and organs organized into a negative feedback system.

Core Concepts and the Physiology Curriculum

We begin by defining what we mean by a “curriculum” and describing the critical features of a curriculum. We next describe the enormous diversity of students and programs in physiology and how the curricula reflect this diversity. We then propose how each of the three core concepts we have detailed can be sequenced through the courses that make up a curriculum. Finally, we consider how to assess student mastery of the core concepts across the courses that make up the curriculum.

Organizing an Introductory Physiology Course Based on Core Concepts

We begin by defining a typical sequence of topics that make up an introductory physiology course. We then describe how one might introduce students in the course to the core concepts and general models. We then discuss how to revisit the core concepts as they occur in the physiology being learned. What is essential is the use of consistent terminology and visual representations of the core concepts. It is also essential that the learning objectives (the definition of what is required for student mastery) include the recognition and use of the core concepts. We end with a discussion of the time constraints that are associated with every course while at the same time adding an emphasis on the core concepts.

The “Unpacked” Core Concept of Flow Down Gradients

The core concept of flow down gradients is also a general model of how things, whether animate or inanimate, move in the physical world.