Introduction
The human body is wonderfully elegant in its composition and operation, at once a complex assemblage of structures and an aggregation of simple, often intuitive, functions. The content of my Anatomy and Physiology course is organized around a central concept: Mr. Adu-Wusu’s 3 P’s of Anatomy and Physiology (Figure 1). The 3 P’s are as follows: Parts, Purpose, Peril. Alternatively, they can be considered in the framework of anatomy-physiology-dysfunction or structure-function-dysfunction. The basic principle holds that the body is comprised of structures whose compositions dictate the functions they can perform and thus, changes in structure can lead to dysfunction.
As an example, consider the skin. The outermost layer consists of tightly-packed, flattened cells filled with the protein keratin. The arrangement of these epidermal components allows the integumentary system to serve a barrier function, rebuffing transport of water, germs, and other unwanted foreign substances. Any event that breaks the continuity of this layer (e.g. penetration by a sharp object) diminishes the ability of the skin to function as a protective barrier. Necessarily then, remedies to address such dysfunctions (e.g. adhesive bandages, surgical stitches, scab formation, etc.) seek to restore the physical integrity of the epidermis that enables its appropriate function.
When considered in this way, the workings of the body are much less a set of enigmatic phenomena, and much more so a known or knowable system that can be understood through experimentation and data analysis: research. As my students come to internalize this fundamental construction, they can view various health ailments – disease, injury, aging, etc. – as just changes in functional capability owing to changes in structure. It follows then that solutions (actual and potential) for bodily infirmities result from restoration of normal structure and/or mitigating the effects of abnormal structure. Simply put, my goal is for my students to embrace the idea that we explore the parts of the body, so we can know how those parts work, because it is by understanding how the parts work, that we might be able to fix any problems that arise. In this structure-function-dysfunction framework, students can explore and better understand anatomical and physiological topics ranging from relatively simple skin lacerations and bone fractures to more complex gastrointestinal disorders and autoimmune diseases.
Throughout the course, the paradigm of the 3 P’s is applied to the various organ systems of the body. The curriculum unit presented here is to be a short segment taught within the portion of the course that covers the structure, function, and dysfunction of the muscular system. Prior to the curriculum unit, students have come to understand that the structures of the muscular system cooperate to perform several critical functions; muscles generate movement of body parts and help to maintain joint stability; muscles help to provide the shape/structure for the body and help to maintain posture; muscles produce heat to help maintain body temperature (homeostasis); muscles help to protect internal organs; muscle contractions enable movement of blood and food/nutrients through the body.
The curriculum unit establishes Duchenne muscular dystrophy (DMD) as one of the representative disorders that students can explore in order to gain a better understanding of normal and abnormal functioning of the muscular system. The curriculum unit also presents a simplified framing device through which students can grasp the molecular basis of gene therapy. Advances in gene therapy for the treatment of DMD are presented as concrete examples to reinforce the central idea that even complex remedies fit the simple paradigm of regaining function by restoring structure.
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