Getting Skin in the Game: A lesson on the structure and function of the body’s innate physical barriers using open educational resources

The concept of a physical barrier in the human body is foundational to understanding the pathogenesis of disease. The human body’s first line of defense is its natural coverings forming a contiguous barrier that employ various strategies to combat external threats from foreign substances and pathogenic microorganisms. The integrity and normal function of these barriers is therefore paramount for health and when they fail, are damaged or disrupted, it underpins many diseases. These barriers are constructed from some of the body’s most basic of tissues: epithelia and their underlying connective tissues. It is therefore important for medical, dental and allied health students to understand how these cells and tissues are assembled to carry out their essential physiological functions.

The skin, for example, has numerous strategies to form a protective barrier – its surface epidermis is stratified, with its keratinocytes held together by numerous cell junctions to maintain integrity; its surface contains several layers of dead keratinocytes (corneocytes) to combat abrasion; dying keratinocytes within the granular layer release lamellar bodies that contain waterproofing lipids and antimicrobial peptides that surround corneocytes; resident antigen-presenting dendritic cells form a network within the epidermis to trap invading microbes. Within loose connective tissue of the papillary dermis, resident mast cells may release mediators to initiate inflammatory responses, attracting other immune cells to the site of infection.

For many, obtaining access to the educational resources to teach this functional histology can be difficult. Not only locating them, but also finding examples that are engaging, can be adapted and/or sit on a platform that is readily accessible to students. During this session you will see some of the resources that we have created and use in our own teaching (Virtual Microscopy; YouTube channels; Twitter threads and Instagram quizzes) that are freely available to support academics and students alike.