Using simple conversational language and vivid animations and illustrations structure function of the body 16th edition introduces the normal structure and function of the human body and what the body does to maintain homeostasis. An organ is a group of tissues that constitutes a distinct structural and functional unit thus the heart is an organ composed of all four tissues whose function is to pump blood throughout the body of course the heart does not function in isolation it is part of a system composed of blood and blood vessels as well. The human body is a complex system with structures ranging from cells to organ systems and functions ranging from waste removal to protection and defense the structures and functions are dedicated. The skeletal system your bones cartilage and ligaments provide a structural framework for the rest of you like a scaffolding for organs and tissues this system affords protection of vital organs and permits locomotion of the organism the bone marrow in the middle of long bones makes immune cells