There are five main types of bone in the human body: long bones which are longer than wide and act as levers like the femur and humerus; short bones that are as long as they are wide and provide support and stability; flat bones that are flat plates which provide protection like the scapula and sternum; irregular bones that do not fall into other categories like the vertebrae and sacrum; and sesamoid bones, with the patella being the only type, which resemble sesame seeds.