Human body to comparative physiology and ecophysiology. Most recently, evolutionary physiology has become a distinct subdiscipline. Human body The human body is the 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. It comprises a head, neck, trunk (which includes the thorax and abdomen), arms and hands, legs and feet. 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
Anatomical terms of location the x, y, and z axes familiar from three-dimensional geometry. The terms "intermediate", "ipsilateral", "contralateral", "superficial", and "deep", while indicating directions, are relative terms and thus do not properly define fixed anatomical axes. Also, while the "rostrocaudal" and anteroposterior directionality are equivalent in a significant portion of the human body, they are different directions in other parts of the body. In anatomical terminology superior () is used to refer to what is above something, and inferior () to what is below it. For example, in the anatomical position the most superior part of the human body is the head, and