Depending on the school where you are enrolling, subjects may have a little difference when compared. There are CNA classes where subjects offered might vary to the subject offered by another school. All schools offering CNA programs will be including some basic and fundamental subjects in their classes. These main subjects which must be taught to the students are basic nursing skills, anatomy and physiology, nutrition and infection control. Most science courses or subject are involved in the lessons for CNA students. So it is very much important that you should have taken science subjects during your high school years to be prepared when taking nursing courses.