Blood and Guts covers the major body systems and has a nice handful of experiments and activities to do, including dissections. The physiology is good, though the simple line drawings don't really capture anatomy well.
I am pairing this up with The Body Book by Donald Silver. This book is filled with reproducible pages to be used to make large organ models. This book better covers anatomy, especially if you decide against dissection. It has more activities and some physiology as well.