osteoblast

(noun)

a mononucleate cell from which bone develops

Related Terms

Examples of osteoblast in the following topics:

  • Cell Types in Bones

    • As the secreted matrix surrounding the osteoblast calcifies, the osteoblast becomes trapped within it.
    • As is the case with osteoblasts, osteocytes lack mitotic activity.
    • When they differentiate, they develop into osteoblasts.
    • Osteoclasts continually break down old bone while osteoblasts continually form new bone.
    • Osteogenic cells are undifferentiated and develop into osteoblasts.

  • Bone Development

    • Ossification, or osteogenesis, is the process of bone formation by osteoblasts.
    • They then differentiate into osteoblasts at the ossification center.
    • Osteoblasts secrete the extracellular matrix and deposit calcium, which hardens the matrix.
    • Blood vessels invade the cavities, while osteoblasts and osteoclasts modify the calcified cartilage matrix into spongy bone.
    • Secondary ossification centers form in the epiphyses as blood vessels and osteoblasts enter these areas and convert hyaline cartilage into spongy bone.

  • Bone Remodeling and Repair

    • It involves the processes of bone deposition or bone production done by osteoblasts and bone resorption done by osteoclasts, which break down old bone.
    • Though fragments of the blood clot may remain, fibroblasts and osteoblasts enter the area and begin to reform bone.
    • Fibroblasts produce collagen fibers that connect the broken bone ends, while osteoblasts start to form spongy bone.
    • This is similar to the endochondral formation of bone when cartilage becomes ossified; osteoblasts, osteoclasts, and bone matrix are present.
    • Bone remodeling: The bony callus is then remodelled by osteoclasts and osteoblasts, with excess material on the exterior of the bone and within the medullary cavity being removed.

  • Hormonal Control of Blood Calcium Levels

    • PTH also inhibits osteoblasts, cells which deposit bone, reducing calcium deposition in bone.
    • Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys.

  • Growth of Bone

    • Capillaries and osteoblasts from the diaphysis penetrate this zone.
    • The osteoblasts secrete bone tissue on the remaining calcified cartilage.
    • At the same time, osteoblasts via intramembranous ossification, produce new bone tissue beneath the periosteum.

  • Connective Tissues: Bone, Adipose, and Blood

    • There are three types of cells in bone: osteoblasts, osteocytes, and osteoclasts.
    • Osteoblasts are active in making bone for growth and remodeling.
    • (c) Osteoblasts surround the exterior of the bone.

  • Hormonal Regulation of Growth

    • IGF-1 also has stimulatory effects on osteoblast and chondrocyte activity to promote bone growth.

  • Parathyroid Glands

    • First, PTH enhances reabsorption of calcium by the kidneys; it then stimulates osteoclast activity and inhibits osteoblast activity.