SECTION II
High-Yield General Principles
How to Use the Database“There comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.”
—Sir Arthur Conan Doyle, A Study in Scarlet
“Never regard study as a duty, but as the enviable opportunity to learn.”
—Albert Einstein
“Live as if you were to die tomorrow. Learn as if you were to live forever.”
—Gandhi
HOW TO USE THE DATABASE
The 2018 edition of First Aid for the USMLE Step 1 contains a revised and expanded database of basic science material that students, student authors, and faculty authors have identified as high yield for board review. The information is presented in a partially organ-based format. Hence, Section II is devoted to the foundational principles of biochemistry, microbiology, immunology, basic pathology, basic pharmacology, and public health sciences. Section III focuses on organ systems, with subsections covering the embryology, anatomy and histology, physiology, clinical pathology, and clinical pharmacology relevant to each. Each subsection is then divided into smaller topic areas containing related facts. Individual facts are generally presented in a three-column format, with the Title of the fact in the first column, the Description of the fact in the second column, and the Mnemonic or Special Note in the third column. Some facts do not have a mnemonic and are presented in a two-column format. Others are presented in list or tabular form in order to emphasize key associations.
The database structure used in Sections II and III is useful for reviewing material already learned. These sections are not ideal for learning complex or highly conceptual material for the first time.
The database of high-yield facts is not comprehensive. Use it to complement your core study material and not as your primary study source. The facts and notes have been condensed and edited to emphasize the essential material, and as a result, each entry is “incomplete” and arguably “over-simplified.” Often, the more you research a topic, the more complex it becomes, with certain topics resisting simplification. Work with the material, add your own notes and mnemonics, and recognize that not all memory techniques work for all students.
We update the database of high-yield facts annually to keep current with new trends in boards emphasis, including clinical relevance. However, we must note that inevitably many other high-yield topics are not yet included in our database.
We actively encourage medical students and faculty to submit high-yield topics, well-written entries, diagrams, clinical images, and useful mnemonics so that we may enhance the database for future students. We also solicit recommendations of alternate tools for study that may be useful in preparing for the examination, such as charts, flash cards, apps, and online resources (see How to Contribute, p. xvii).
Image Acknowledgments
All images and diagrams marked with 
are © USMLE-Rx.com (MedIQ Learning, LLC) and reproduced here by special permission. All images marked with 
are © Dr. Richard P. Usatine, author of The Color Atlas of Family Medicine, The Color Atlas of Internal Medicine, and The Color Atlas of Pediatrics, and are reproduced here by special permission (www.usatinemedia.com). Images and diagrams marked with 
are adapted or reproduced with permission of other sources as listed on page 707. Images and diagrams with no acknowledgment are part of this book.
Disclaimer
The entries in this section reflect student opinions of what is high yield. Because of the diverse sources of material, no attempt has been made to trace or reference the origins of entries individually. We have regarded mnemonics as essentially in the public domain. Errata will gladly be corrected if brought to the attention of the authors, either through our online errata submission form at www.firstaidteam.com or directly by email to firstaidteam@yahoo.com.
Notes
