Anatomy is the study of the biological structure of living things. The term comes from the Greek words meaning to cut up, because knowledge of anatomy was first obtained through dissection. The bodies of human beings and animals are so complex that scientists divide anatomy into many branches. Gross anatomy is the study of structures that can be seen with the unaided eye. Microscopic anatomy, or histology, is the study of tissues under a microscope. Comparative anatomy compares the structure of different animals. Embryology is the study of the development of plants and animals in their earliest stages.
Human anatomy includes the study of the structure of the skeleton, muscles, nerves, and the various organs of the human body. A knowledge of the structure of the body is essential for an understanding of its function in health and disease. Health-care professionals must know the structure of the part of the body they expect to treat. Physical education and health science teachers also need to know how the body is built.
In ancient times, people believed that the dead body was a sacred thing. Cutting it up ranked as a serious crime. After 400 B.C., the Greeks allowed occasional dissections. The physician Galen, in the A.D. 100’s, described many anatomical structures. But he based his work mainly on dissections of animals and treatment of injured gladiators. After A.D. 1300, dissection and anatomy became a recognized part of medical education in western Europe. In 1543, Andreas Vesalius published his classic work on anatomy, which was based on human dissections. Since then, steady progress has made possible such discoveries as William Harvey’s on blood circulation. Because of present knowledge of the body’s structure and function, a surgeon can operate on every part of the body. 
