Musculoskeletal System - 2 | Bone Tissue | Bone Types

Bone Tissue A bone is a complex structure, shaped for its particular position in the skeleton and the stress it has to bear. Bone tissue also known as osseous tissue or bone in the uncountable is a form of hard tissue, specialized connective tissue that is mineralized and has an intercellular honeycomb-like matrix, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells: osteoblasts and osteocytes (bone formation and mineralisation); osteoclasts (bone resorption); modified or flattened osteoblasts i.e bone lining cells that form a protective layer on the bone surface. The mineralised matrix of bone tissue has an organic component of mainly ossein, a form of collagen, and an inorganic component of bone mineral, made up of various salts. Bone tissue is classified as compact or Cortical bone and Cancellous or trabecular or spongy bone and depends on how the bone matrix and cells are organized, although bones may also contain other kinds of tissue including bone marrow, endosteum, periosteum, nerves, blood vessels, and cartilage. The amount of cortical or trabecular tissue is depend upon the function of the bone. Bone types Bone types can be classified according to the shape and size of the bone. The shapes of bones reflect their functions. It is useful when describing specific bones to begin by stating the type of bone in relation to its shape; for example, the scapula is a large, flat, triangular bone. In terms of bone shape there are five main types of bone: 1. Long bones 2. Short bones 3. Flat bones 4. Irregular bones 5. Sesamoid bones. Short, irregular, flat and sesamoid bones have no shafts or extremities and are diverse in shape and size. Examples include:  Short bones — carpals (wrist)  Irregular bones — vertebrae and some skull bones  Flat bones — sternum, ribs and most skull bones  Sesamoid bones — patella (knee cap).