A long bone is a type of bone found in the skeletal system of vertebrates, characterized by its elongated shape and cylindrical structure. It is one of the five types of bones in the human body, along with short bones, flat bones, irregular bones, and sesamoid bones.
Long bones are primarily responsible for providing support, mobility, and strength to the body. They serve as levers, aiding in movement and enabling locomotion. The structure of a long bone consists of a diaphysis (the shaft) and two metaphyses (the widened ends). The diaphysis is hollow and made up of compact bone, while the metaphyses contain spongy bone and feature epiphyseal plates (growth plates) during childhood and adolescence.
Long bones have distinct anatomical features, including a periosteum (a tough, fibrous membrane) covering the bone's exterior, and an endosteum (a thin, vascular membrane) lining the inner cavities. The medullary cavity, located within the diaphysis, contains bone marrow, where red and yellow marrow are produced.
Long bones also play a crucial role in the production of blood cells through a process called hematopoiesis. The red bone marrow located in the spongy bone produces red blood cells, platelets, and some types of white blood cells, contributing to the body's immune system.
In summary, long bones are elongated and cylindrical bones that provide support, mobility, and strength to the body. They contain distinct anatomical features and contribute to movement, blood cell production, and overall skeletal stability.
