Bone
| Bone | |
|---|---|
A bone dating from the Pleistocene Ice Age of an extinct species of elephant | |
A scanning electronic micrograph of bone at 10,000× magnification | |
| Identifiers | |
| MeSH | D001842 |
| TA98 | A02.0.00.000 |
| TA2 | 366, 377 |
| TH | H3.01.00.0.00001 |
| FMA | 5018 |
| Anatomical terminology | |
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals.[1] Bones protect the organs of the body, produce red and white blood cells, store minerals, help regulate acid-base homeostasis, provide structure and support for the body, and enable mobility and hearing. Bones come in a variety of shapes and sizes and have complex internal and external structures.[2]
Bone tissue (also known as osseous tissue or bone in the uncountable) is a form of hard tissue, specialised connective tissue that is mineralized and has an intercellular honeycomb-like matrix,[3] 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 (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 comprises cortical bone and cancellous bone, although bones may also contain other kinds of tissue including bone marrow, endosteum, periosteum, nerves, blood vessels, and cartilage.
In the human body at birth, approximately 300 bones are present. Many of these fuse together during development, leaving a total of 206 separate bones in the adult, not counting numerous small sesamoid bones.[4][5] The largest bone in the body is the femur or thigh-bone, and the smallest is the stapes in the middle ear.
The Ancient Greek word for bone is ὀστέον ("osteon"). In anatomical terminology, including in the Terminologia Anatomica, the word for a bone is os (for example, os breve, os longum, os sesamoideum).
- ^ Lee C (January 2001). The Bone Organ System: Form and Function. Academic Press. pp. 3–20. doi:10.1016/B978-012470862-4/50002-7. ISBN 978-0-12-470862-4. Retrieved 30 January 2022 – via Science Direct.
- ^ de Buffrénil V, de Ricqlès AJ, Zylberberg L, Padian K, Laurin M, Quilhac A (2021). Vertebrate skeletal histology and paleohistology (First ed.). Boca Raton, FL: CRC Press. pp. xii + 825. ISBN 978-1-351-18957-6.
- ^ Langley, Natalie, Tersigni-Terrant, Maria-Teresa, eds. (2017). Forensic Anthropology: A Comprehensive Approach (2nd ed.). CRC Press. p. 82. ISBN 978-1-315-30003-0.
- ^ Steele DG, Bramblett CA (1988). The Anatomy and Biology of the Human Skeleton. Texas A&M University Press. p. 4. ISBN 978-0-89096-300-5.
- ^ Mammal anatomy: an illustrated guide. New York: Marshall Cavendish. 2010. p. 129. ISBN 978-0-7614-7882-9.