Final answer:
Long bones are composed of the diaphysis (shaft), metaphysis (flared portion), and epiphysis (extremity). They contain both yellow and red bone marrow and are essential for movement and leverage in limbs.
Step-by-step explanation:
Long bones consist of three main parts: the diaphysis (or shaft), metaphysis (or flared portion), and the epiphysis (or extremity). The diaphysis is the long central shaft, which contains bone marrow in a marrow cavity. The metaphysis is the narrow area where the diaphysis meets the epiphysis, including the growth plate in growing bones, which later becomes the epiphyseal line. The epiphysis is the rounded end of the bone, filled with spongy bone and red marrow, which produces blood cells. These structures are covered with articular cartilage at the joint surface. Examples of long bones include the femur, tibia, ulna, and radius. These bones are critical for movement as they function as levers when muscles contract.