I use this human body systems assessment with my advanced 5th grade class. It is quite lengthy, but they complete it in one 50 minute class session. It can be simplified or broken into parts if you have a lower level class, or it can be used in higher grades.
This test and review goes along with the human body systems notes I also have on TpT, as well as a human body 3-d project.
Photos of the answer keys are included in the document.