Anatomy and physiology for medical assistant training?

I am currently attending high school and I have finished all of my work. Now I have the opportunity to study anything I want and I since I have decided to train as a medical assistant, I was considering using the time that I have studying the human anatomy and physiology to have some knowledge before entering a medical program. What should I focus my attention on in this subject? Are there any other subjects you recommend studying along with anatomy and physiology?