The document discusses the endocrine system and medical terminology related to it. It begins by stating that the endocrine system consists of ductless glands that secrete hormones directly into the bloodstream to regulate bodily functions. Endocrinology is the field of medicine focused on studying the endocrine system and treating related diseases. An endocrinologist specializes in the medical practice of endocrinology. The document aims to help students learn the basic structure of medical words, terminology, and connections related to the anatomy and physiology of the endocrine system.