Anatomy is the science of the structure of the body. It is a branch of biology that studies the physical structure of organisms and their parts. ANATOMY is closely related to physiology, which is the study of the functions of the body's parts. ANATOMY is divided into two main branches: gross ANATOMY, which studies the structure of organs and tissues visible to the naked eye, and microscopic ANATOMY, which studies the structure of cells and tissues too small to be seen without a microscope.