Bone is a strong and light connective tissue derived from mesoderm. Although a diversity of connective tissue, such as blood, bone, cartilage and fascia, are all derived from mesoderm, bone has the highest mineral component (50%).
People often think of bone as a 'dead' and unchanging tissue. In
reality it is dynamic, and is continually being broken down and
rebuilt throughout life to suit changing requirements and maintain
normal structure. Bone, like all other tissues of the body is supplied
with blood.
Bone has many functions it provides support and movement via attachments for soft tissue and muscle, it protects vital organs, it is a major site for red marrow for production of blood cells, and it plays a role in the metabolism of minerals such as calcium and phosphorus.
Bone is covered by periosteum, a specialised membrane which acts like a skin around bone and is essential for circumferential bone growth. Bone surfaces within the marrow cavity are covered by a membrane known as the endosteum which contains bone forming cells (osteoblasts).
Bone can be lamellar or woven. Woven bone is immature, and can be found in the embryo or around healing fractures. Lamellar bone is found in the spongy and compact parts of all mature bones.
Long bones are bones that have greater length than width, such
as the femur and tibia in the lower limb. Examples of irregular bones
are the talus, navicular and cuboid in the foot.
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