The document discusses the structural organization of the human body from the chemical level up to the organ system level. It begins by explaining the organization from atoms and molecules, then cells, tissues, organs, and systems. It then provides details on the 11 organ systems that make up the human body: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive systems. Each system is described by its organs and their main functions.