This diagram of various human body systems depicts multiple human body parts. The physical substance of the human organism, composed of living cells and extracellular materials and organized into tissues, organs, and systems, is known as the human body. Many different articles cover human anatomy and physiology. The human body is a vertebrate with an internal skeleton that includes a backbone of vertebrae. As shown in this diagram of the different systems of the human body, the human body has characteristics typical of mammalian structure, such as hair, mammary glands, and highly developed sense organs. The human body primarily comprises water and organic compounds, such as lipids, proteins, carbohydrates, and nucleic acids.