Designed to supplement curricular programs dealing with the human body, this booklet offers an activity-based, student-oriented approach for middle school teachers and students. Twelve activities focus on principles and skills related to the respiratory, circulatory, and skeletal systems. Each activity consists of student sheets and a teacher's guide. The teacher's guide contains information on the activities including: (1) topic area; (2) introductory statement; (3) math and science skills; (4) required materials; (5) key questions; (6) background information; (7) management details; (8) instructional procedures; (9) student procedures; (10) discussion questions; (11) activity extensions; and (12) curriculum coordinates. (ML)