Our "spine" is My Body. This is a very unique little book. Each page is dedicated to one or more topics (skeleton, heart and lungs, brain...). There is a paragraph or two, which I read aloud to her. But the best part is that each page includes a paper model to color and cut out. I photocopy the page so we can keep the book intact. Once it's cut out, we attach the model to our "paper person", which hangs on the door of our home library. I had her lie down on a large piece of paper so that I could trace her for this. You can see that I probably should have flunked kindergarten due to poor cutting skills!
The second thing we do every week is to read about our "organ of the week" in the Kingfisher First Human Body Encyclopedia. The one that we are using is out of print, but could easily be replaced by another encyclopedia.
To wrap up the week, we do an activity or two from Everybody Has a Body.
This is a book I already owned, otherwise I do not think I would pay the current list price for it! The activities in the book are fairly simple, which is fine for her right now. So far we have done things like guessed which parts of her body would be the most ticklish (and then testing with a feather), collected some objects and guessed which ones she would be able to pick up with her hands versus her feet, and things like that. The activities are mostly very minimal prep and take only a few minutes to do. It is geared towards a classroom setting, but most of the activities are do-able or adaptable for homeschool. I do not correlate the activities with the readings, we just work though the book at our own pace.
We have also enjoyed reading The Magic School Bus Inside the Human Body over and over. Our copy is very well-loved!
And I have the Magic School Bus website bookmarked for additional experiments and games if we want them.
And that is how we are studying the human body this year!