Tortora’s Principles of Anatomy and Physiology comes highly recommended as an anatomy and physiology text, and should serve as a good foundation for more advanced studies in anatomy and physiology. After you have mastered Tortora you may want to take a look at Guyton's text on physiology.
Biology by Campbell and Biological Science by Freeman were written for students who do not have a background in science. The books cover topics of cells, immunology, and gas exchange in enough detail to allow you to study anatomy and physiology in more depth. You will notice that the biology texts contain animal examples as well as human examples. You can just skip over the animal examples!
Biology (Campbell) Recommended Sections
Biological Science (Freeman) Recommended Sections