It is important to state the central tenet of this paper: A firm understanding of the basic sciences is necessary for the intelligent practice of medicine. It is also important to acknowledge our inherent conflict of interest in writing this paper. As physiologists, we have chosen to make medical student education a major component of our professional career. Our bias is unavoidable, and to deny it would be to deny our professional identity.
As with most professionals, physicians function in multiple roles, including technologist, scientist, and humanist. Importantly, these roles are not mutually exclusive. This paper will advocate the role of the physiological sciences in developing the physician as scientist, but in doing so we do not seek to dismiss the other important roles of the physician, nor the contributions of the physiological sciences to those roles.
There are two aspects to the physiological sciences: physiology and scientist. Too often, the discipline is identified by the content (physiology) and not the role (scientist). The physiology aspect centers on a knowledge base which emphasizes principles of integration and control. The same efferent control system is responsible for shifting from the steady-state balance of homeostasis to an adaptive response which enables an organism to survive when the environmental situation changes. Physiological control emphasizes why, for example, the normal homeostatic heart rate of 72 beats per minute is inappropriate during aerobic exercise.
The scientist role of our discipline is equally as important in the development of a physician. This aspect of the preclinical curriculum is no less important than the knowledge fund, but it generally receives much less attention. Competent physicians must be able to evaluate research outcomes and incorporate them into their clinical practice. In the past 20 years, identifying the research which leads to best clinical practices has been formalized as “evidence-based medicine”. Physicians in their role as scientists have to understand research processes and topics.
What Sciences Constitute the Foundation for Medical Practice?
The sciences that describe the body constitute the foundation for medical practice. This description exists at many levels: genetic, cellular, organ, organism, and population. The discipline of physiology describes function at each level from genetic to population. Most commonly, physiology is concerned with the function of organs and organisms. Physiology, however, does not exist in isolation. A proper understanding of physiology requires the context provided by the anatomical sciences, both gross and microscopic. In many allied health programs, instruction in anatomy and physiology are paired in recognition of this fact. Digestive and metabolic physiology are inseparable from biochemistry. Physiology, in turn, is a foundational science for other disciplines. The physiology of the various organs interacts with aspects of pharmacology and pathology. In a relatively recent development, the essential involvement of immune system mediators in both normal function and in disease is being better characterized. It is this interaction among the basic sciences that is emphasized in systems-based educational programs.
What is the Value and Role of Foundational Sciences in Medical Education?
Each of the basic sciences is a freestanding discipline in its own right with its own role and perspective. The anatomical sciences emphasize location in three dimensions, with the emphasis on both the details of an individual structure and its relationship to other structures in the body. Physiology deals with the same structures, but from a different perspective. Physiology emphasizes the organization and control of bodily function, both at the individual organ level and in dealing with the interactions between multiple organ systems. Such an approach has made it clear that organ system function varies over time. The body constantly balances the need for homeostasis with the ability to adapt to changing environment, such as caused by the introduction or the restriction of nutrients. These interactions are complex and are most commonly described in graphs and concept maps. It is not a coincidence that the most common x-axis used in physiology deals with some aspect of time. Physiology encourages students to embrace the huge quantities of data that are encountered in a typical patient presentation and to identify underlying themes that make sense of the observations. This ability to juggle data and context is essential when developing the hypotheses necessary to the clinical reasoning process.
The value of the preclinical sciences is that they promote an understanding of the body from multiple perspectives. There are times where the anatomical perspective provides insight and an enhanced ability to interpret symptoms such as localized pain. There are times that a physiological perspective is necessary to interpret a vital sign such as an elevated heart rate. Each of the preclinical sciences can make a similar argument, and it is the availability of the multiple perspectives provided by the basic sciences that allows a well-educated physician to interpret correctly complex clinical cases.
When and how should these foundational sciences be incorporated into the medical education curriculum?
Foundational sciences should be incorporated into the medical education curriculum in a manner which best facilitates their acquisition and retention. How to best facilitate acquisition and retention, however, is the subject of ongoing debate. On the acquisition side, learning theory shows that repetition enhances recall. Curricula should have planned redundancies, and the “spiral curriculum” exploits this approach. Layered on top of learning theory is the debate about the residual value of information that is learned and later forgotten. Something learned once, then forgotten, is often easier to learn the second time. Although some of the concepts in the preclinical years may be forgotten, they will be mastered more quickly upon second exposure in the clinics. On the retention side, one key tenet of adult learning theory is that information is retained best when it is integrated with prior information, and presented in the context in which it will be used. The problem-based and case-based approaches are designed in part around the ability to place knowledge in the appropriate context.
How to best achieve these aims for physiology has resulted in this discipline being represented in a wide variety of approaches to preclinical education. In the post-Flexnerian era, physiology was usually presented in a course during the preclinical years, occasionally combined with neurophysiology, endocrinology, or some other preclinical science. More recently, the evolution of integrated curricula resulted in the content traditionally defined as physiology often being a component of systems-based preclinical instruction. The lack of a single optimal curricular approach in US medical schools reflects both the complexity of the cognitive processes and the constraints in resources faced by each individual institution. The educational approach is optimized to the constraints (space, personnel other resources) faced by individual institutions.
What Sciences should be a Prerequisite of a Pre-Medical Curriculum?
The dividing line between the preclinical medical curriculum and premedical baccalaureate curriculum is artificial and arbitrary. The diversity of educational programs around the globe that do not include an undergraduate experience yet successfully prepare clinicians is evidence of this ill-defined boundary. Nevertheless, biology and chemistry certainly are core sciences necessary to pursue clinical training, and it is probably irrelevant if they are mastered as part of undergraduate training or the initial years of a dedicated medical curriculum. In preparation for physiology, an appreciation of the anatomical sciences and biochemistry provide a foundation on which physiological principles can be elucidated.
What are the Best Practices for Placing Foundational Sciences into the Medical Curriculum?
Educational research is fraught with inherent limitations. In terms of experimental design, confounders include the cohort effect and the Hawthorne effect. The cohort effect results from the fact that no two groups of students are identical, and consequently assessing the effects of an impact on one group of students versus another does not always yield clear differences. In addition, innovation alone enhances learning (see description of the Hawthorne Effect). Adding to the inherent design limitations of educational experiments, the desired outcome of a medical curriculum is exceptionally difficult to quantitate. Consequently, the best practices in incorporating the foundational science into medical education are defined pragmatically as those that work. In some environments, it is a faculty-centered model, such as the discipline-based approach proposed in the Flexner report. In other environments, it is a student-directed model such as problem-based learning. In all curriculum models, there is a constant tension between the breadth of content expectations, and the value of deep learning, all constrained by time limitations.
It is an interesting time to consider the role and value of basic sciences and medical education. The absence of an idealized model for medical education raises the question of whether the curriculum really has an impact. Many argue, for example, that our students’ learning is independent of the curriculum, or in a worse case scenario, in spite of the curriculum. The Flexner model, which has guided the past century of medical education in the United States, is being increasingly challenged. In these uncertain times, it is important to remain grounded in the central duties of educators: to create an environment that enhances learning, to provide direction for the learners, and to model appropriate learning behaviors.