Human Anatomy and Physiology is a free, complete two-semester A&P textbook written for the people who actually take the course — nursing and pre-nursing students, pre-med and pre-PA applicants, kinesiology and exercise science majors, dental hygiene students, EMTs and paramedics, and anyone who wants to understand the body they live in. It covers the full 33-chapter sequence at the depth the gateway course demands, and it is free, because a required course that gates entry to the health professions should not also cost $300.
The book is built around one organising idea: structure explains function, and neither is memorable alone. Part I lays the foundations — anatomical language and the levels of organisation, the chemistry that physiology runs on, cells, and tissues. Part II covers support and movement through the integumentary system, bone tissue, the skeleton, joints, and two chapters on muscle that separate the mechanics of contraction from the muscular system itself. Part III takes on regulation and integration: neurons and the action potential, the central and peripheral nervous systems, autonomic control, the special senses, and the endocrine system. Part IV works through maintenance — blood, the heart, the vessels, lymphatics, immunity, respiration, digestion, nutrition and metabolism, thermoregulation, and the urinary system. Parts V and VI close with continuity and integration: reproduction, development, genetics, aging, fluid and acid-base balance, exercise physiology, and a capstone that puts every system back together.
Two features run through all 33 chapters. Each opens with a clinical Case File you cannot explain on the first page and can fully explain by the last, following one patient — Amara Osei, a night-shift charge nurse — from an ambiguous chest pressure through the systems that produced it. And every diagram is paired with a written description, so the book works for readers using screen readers, studying on a phone, or printing in black and white. Predict-then-check boxes, histology and imaging callouts, lifespan and development notes, and a chapter-by-chapter self-assessment tracker make it usable for self-study as well as for a formal course, with an instructor companion providing pacing guides, laboratory alignment, an assessment bank, and rubrics.