Bone remodeling
TGF-β, IGF
) signalling.In
bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation). These processes also control the reshaping or replacement of bone following injuries like fractures but also micro-damage
, which occurs during normal activity. Remodeling responds also to functional demands of the mechanical loading.
In the first year of life, almost 100% of the skeleton is replaced. In adults, remodeling proceeds at about 10% per year.[1]
An imbalance in the regulation of bone remodeling's two sub-processes, bone resorption and bone formation, results in many metabolic bone diseases, such as osteoporosis.[2]
Physiology
Bone
VEGF and IL-6 family).[5] It is in this way that the body is able to maintain proper levels of calcium
required for physiological processes. Thus bone remodeling is not just occasional "repair of bone damage" but rather an active, continual process that is always happening in a healthy body.
Subsequent to appropriate signaling, osteoclasts move to resorb the surface of the bone, followed by deposition of bone by osteoblasts. Together, the cells that are responsible for bone remodeling are known as the basic multicellular unit (BMU), and the temporal duration (i.e. lifespan) of the BMU is referred to as the bone remodeling period.[6]
Gallery
-
Osteoblasts actively synthesizing osteoid containing two osteocytes. -
Osteoclast, with bone below it, showing typical distinguishing characteristics: a large cell with multiple nuclei and a "foamy" cytosol. -
Illustration showing bone remodelling cycle
.jpg)
See also
- Biomineralization, the general class of forming and maintaining mineralized tissues
- Tissue remodeling
- Wolff's law
References
- ^ Wheeless Textbook
- ^ Online Medical Dictionary
- PMID 20501658.
- PMID 24466412.
- PMID 36410109.
- ISBN 1-58829-909-0page 48