Human anatomy is the study of the systems of the body which is made up of cells, tissues, and organs. Human anatomy is important to study to help explain how organs and other structures of the body work. There are eight systems in the human body. Each system relies on the other to keep the body functioning. The systems of the body includes the circulatory, immune, skeletal, excretory, muscular, endocrine, digestive, nervous and respiratory. It is important to understand how human body systems work together.