In
histological specimenHistology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining a thin slice of tissue under a light microscope or electron microscope...
,
osteoid is the unmineralized, organic portion of the bone matrix that forms prior to the maturation of
bone tissueOsseous tissue, or bone tissue, is the major structural and supportive connective tissue of the body. Osseous tissue forms the rigid part of the bone organs that make up the skeletal system.-Formation:Bone tissue is a mineralized connective tissue...
.
OsteoblastAn osteoblast is a mononucleate cell that is responsible for bone formation. Osteoblasts produce osteoid, which is composed mainly of Type I collagen. Osteoblasts are also responsible for mineralization of the osteoid matrix...
s begin the process of forming bone tissue by secreting the osteoid as several specific
proteinsProteins are organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer chain are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues...
. When the osteoid becomes
mineralizedIn biology, mineralization refers to the process where an organic substance is converted to or becomes impregnated with an inorganic substance.This may also be a normal biological process which takes place during the life of an organism such as the formation of bone tissue or egg shells, largely...
, it and the adjacent bone cells have developed into new bone tissue.
Osteoid makes up about fifty percent of bone volume and twenty-five percent of bone weight.
In
histological specimenHistology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining a thin slice of tissue under a light microscope or electron microscope...
,
osteoid is the unmineralized, organic portion of the bone matrix that forms prior to the maturation of
bone tissueOsseous tissue, or bone tissue, is the major structural and supportive connective tissue of the body. Osseous tissue forms the rigid part of the bone organs that make up the skeletal system.-Formation:Bone tissue is a mineralized connective tissue...
.
OsteoblastAn osteoblast is a mononucleate cell that is responsible for bone formation. Osteoblasts produce osteoid, which is composed mainly of Type I collagen. Osteoblasts are also responsible for mineralization of the osteoid matrix...
s begin the process of forming bone tissue by secreting the osteoid as several specific
proteinsProteins are organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer chain are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues...
. When the osteoid becomes
mineralizedIn biology, mineralization refers to the process where an organic substance is converted to or becomes impregnated with an inorganic substance.This may also be a normal biological process which takes place during the life of an organism such as the formation of bone tissue or egg shells, largely...
, it and the adjacent bone cells have developed into new bone tissue.
Osteoid makes up about fifty percent of bone volume and twenty-five percent of bone weight. It is composed of
fibersScleroproteins are one of the two main classes of protein Quaternary structure .They are also called fibrous proteins.-Characteristics:...
and
ground substanceGround substance is a term for the non-cellular components of extracellular matrix containing the fibers.It is usually not visible on slides, because it is removed during the preparation process....
. The predominant fiber-type is Type I
collagenCollagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content. It is naturally found exclusively in metazoa, including sponges. In muscle tissue it serves as a major component of endomysium...
. The ground substance is mostly made up of
chondroitin sulfateChondroitin sulfate is a sulfated glycosaminoglycan composed of a chain of alternating sugars . It is usually found attached to proteins as part of a proteoglycan. A chondroitin chain can have over 100 individual sugars, each of which can be sulfated in variable positions and quantities...
and
osteocalcinOsteocalcin is a noncollagenous protein found in bone and dentin. It is secreted by osteoblasts and thought to play a role in mineralization and calcium ion homeostasis...
.
When there is insufficient mineral or osteoblast dysfunction, the osteoid does not mineralize properly, and it accumulates. This process is called
osteomalaciaOsteomalacia term for the softening of the bones due to defective bone mineralization. Osteomalacia in children is known as rickets, and because of this, use of the term osteomalacia is often restricted to the milder, adult form of the disease. It may show signs as diffuse body pains, muscle...
. Osteomalacia, when present in children, is defined as
ricketsRickets is a softening of bones in children potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D deficiency, but lack of adequate calcium in the diet may also lead to rickets...
.
External links
- "Bone, femur"