Osteoid

Osteoid
Osteoid
	Light micrographofosteoid,containing twoosteocytes,being synthesized byosteoblasts.
Identifiers
FMA	66830
	Anatomical terminology [edit on Wikidata]

Inhistology,osteoidis the unmineralized, organic portion of the bone matrix that forms prior to the maturation ofbone tissue.^[1]Osteoblastsbegin the process of forming bone tissue by secreting the osteoid as several specificproteins.The osteoid and its adjacentbone cellshave developed into new bone tissue when it becomesmineralized.

Osteoid makes up about fifty percent of bone volume and forty percent of bone weight. It is composed offibersandground substance.The predominant type of fiber is type Icollagenand comprises ninety percent of the osteoid. The ground substance is mostly made up ofchondroitin sulfateandosteocalcin.

Disorders

When there are insufficient nutrient minerals or osteoblast dysfunction, the osteoid does not mineralize properly and accumulates. The resultant disorder is termedricketsin children andosteomalaciain adults. A deficiency of type I collagen, such as inosteogenesis imperfecta,also leads to defective osteoid and brittle, fracture-prone bones.

In some cases,secondary hyperparathyroidismcan cause a disturbance in mineralisation of calcium and phosphate.

Another condition is a disturbance in primitive transformed cells of mesenchymal origin, which exhibit osteoblastic differentiation and produce malignant osteoid. This results in the formation of a malignant primary bone tumor known asosteosarcomaor osteogenic sarcoma. This malignancy most often develops in adolescence during periods of rapid osteoid formation (commonly referred to as growth spurts).^[2]

References

^Trammell, Lindsay H.; Kroman, Anne M. (2013-01-01), DiGangi, Elizabeth A.; Moore, Megan K. (eds.),"Chapter 13 - Bone and Dental Histology",Research Methods in Human Skeletal Biology,Academic Press, pp.361–395,doi:10.1016/b978-0-12-385189-5.00013-3,ISBN 978-0-12-385189-5,retrieved2020-11-18
^Ottaviani Giulia; Jaffe Norman (2009). "The Epidemiology of Osteosarcoma".Pediatric and Adolescent Osteosarcoma.Cancer Treatment and Research. Vol. 152. New York: Springer. pp.3–13.doi:10.1007/978-1-4419-0284-9_1.ISBN 978-1-4419-0283-2.PMID 20213383.

Netter, Frank H. (1987),Musculoskeletal system: anatomy, physiology, and metabolic disorders,Summit, New Jersey: Ciba-Geigy Corporation
Jaffe, N.; et al. (2009).Pediatric and Adolescent Osteosarcoma.New York: Springer.ISBN 978-1-4419-0283-2.

External links

Histology image: 69_03at the University of Oklahoma Health Sciences Center - "Bone, femur"
Dr. Susan Ott's website on osteomalacia

[1] Trammell, Lindsay H.; Kroman, Anne M. (2013-01-01), DiGangi, Elizabeth A.; Moore, Megan K. (eds.),"Chapter 13 - Bone and Dental Histology",Research Methods in Human Skeletal Biology,Academic Press, pp.361–395,doi:10.1016/b978-0-12-385189-5.00013-3,ISBN 978-0-12-385189-5,retrieved2020-11-18

[2] Ottaviani Giulia; Jaffe Norman (2009). "The Epidemiology of Osteosarcoma".Pediatric and Adolescent Osteosarcoma.Cancer Treatment and Research. Vol. 152. New York: Springer. pp.3–13.doi:10.1007/978-1-4419-0284-9_1.ISBN 978-1-4419-0283-2.PMID 20213383.

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