<P> The human body is the entire structure of a human being . It is composed of many different types of cells that together create tissues and subsequently organ systems . They ensure homeostasis and the viability of the human body . </P> <P> It comprises a head, neck, trunk (which includes the thorax and abdomen), arms and hands, legs and feet . </P> <P> The study of the human body involves anatomy, physiology, histology and embryology . The body varies anatomically in known ways . Physiology focuses on the systems and organs of the human body and their functions . Many systems and mechanisms interact in order to maintain homeostasis, with safe levels of substances such as sugar and oxygen in the blood . </P> <P> The body is studied by health professionals, physiologists, anatomists, and by artists to assist them in their work . </P>

The study of the structure of the body is known as