As a university discipline, Histology is studied in the early years of various health sciences courses. It is particularly relevant to medical studies. Microscopy lab sessions are a necessary complement to theoretical knowledge, allowing students to identify cells and tissues under a light microscope. The interpretation of transmission electron microscopy (TEM) images is much more complex and is usually covered only in theoretical classes, though not in great depth, leading to a learning deficit that becomes evident in more advanced courses.

This work is a pilot study demonstrating the TEM learning acquired by freshmen medical students using a practical booklet in an atlas format, developed within the department. Students enrolled in the Cellular Biology and Histology lab sessions dedicate only 1.5 hours to electron microscopy. Until the 2024-2025 academic year, they did not have a booklet with physical photographs for study. Faculty members created a booklet featuring TEM images aligned with the student’s theoretical knowledge and included explanations for each image. The booklets were made available to students, and after an instructor's explanation, they were guided on which images to study during the practice session.

To assess the student’s learning progress, they were invited to take two tests, one at the beginning of the session to evaluate their prior knowledge and one at the end to measure their learning outcomes. At the start of the activity, one-third of the students reported being unable to recognize the images as TEM photographs and 93% were unable to interpret them. However, after the activity, in the final test, approximately 80% of the students were able to correctly identify the indicated organelles and/or structures in the images.

In conclusion, using a faculty-led TEM practice booklet, with real photographs and accompanying explanations, is a feasible and highly effective learning strategy for teaching transmission electron microscopy to freshmen medical students. This tool can also be implemented in other health sciences programs.

Keywords: Health Sciences Education, Histology Education, Electron Microscopy, Undergraduate Perceptions.