chondrocyte

Examples of chondrocyte in the following topics:

• Growth of Bone

  • The reserve zone, the region closest to the epiphyseal end of the plate, contains small chondrocytes within the matrix .
  • The proliferative zone, the next layer toward the diaphysis, contains stacks of slightly-larger chondrocytes .
  • It continually makes new chondrocytes via mitosis.
  • The zone of maturation and hypertrophy contains chondrocytes that are older and larger than those in the proliferative zone .
  • The second zone, the proliferative zone, is where chondrocytes are continually undergoing mitosis.

• Cartilage Growth

  • The chondroblast is now a chondrocyte, which is usually inactive but can still secrete and degrade the matrix depending on the conditions.
  • Once damaged, cartilage has limited repair capabilities because chondrocytes are bound in lacunae and cannot migrate to damaged areas.
  • A chondrocyte, stained for calcium, showing its nucleus (N) and mitochondria (M).

• Development of the Skeleton

  • Chondrocytes in the primary center of ossification begin to grow (hypertrophy).
  • Then calcification of the matrix occurs and the hypertrophic chondrocytes begin to die.
  • The hypertrophic chondrocytes (before apoptosis) secrete Vascular Endothelial Cell Growth Factor that induces the sprouting of blood vessels from the perichondrium.
  • Blood vessels forming the periosteal bud invade the cavity left by the chondrocytes and branch in opposite directions along the length of the shaft.

• Structure, Type, and Location of Cartilage

  • For one, the primary cell types are chondrocytes as opposed to osteocytes.
  • Chondrocytes are first chondroblast cells that produce the collagen extracellular matrix (ECM) and then get caught in the matrix.
  • They lie in spaces called lacunae with up to eight chondrocytes located in each.
  • Chondrocytes rely on diffusion to obtain nutrients as, unlike bone, cartilage is avascular, meaning there are no vessels to carry blood to cartilage tissue.
  • Chondrocytes lie between the fibers.

• Postnatal Bone Growth

  • Quiescent chondrocytes are found here.
  • Zone of cell proliferation: Closer to the marrow cavity, chondrocytes in this region multiply and arrange themselves into longitudinal columns of flattened lacunae.
  • Zone of bone deposition (ossification): The walls between the lacunae break down and the chondrocytes die.

• Cartilaginous Joints: Synchodroses

  • In puberty, increasing levels of estrogen, in both females and males, leads to increased apoptosis of chondrocytes in the epiphyseal plate.
  • Depletion of chondrocytes due to apoptosis leads to less ossification, and growth slows down and later stops when the cartilage has been completely replaced by bone.

• Connective Tissues: Loose, Fibrous, and Cartilage

  • The cells, called chondrocytes (mature cartilage cells), make the matrix and fibers of the tissue.
  • Chondrocytes are found in spaces within the tissue called "lacunae. "
  • Hyaline cartilage consists of a matrix with cells called chondrocytes (shown here) embedded in it.
  • The chondrocytes exist in cavities in the matrix called lacunae.

• Bone Development

  • In long bones, chondrocytes form a template of the hyaline cartilage diaphysis.
  • This calcification prevents diffusion of nutrients into the matrix, resulting in chondrocytes dying and the opening up of cavities in the diaphysis cartilage.

• Hormonal Regulation of Growth

  • Thus, GH exerts some of its effects by binding to receptors on target cells, where it activates a pathway that directly stimulates division and multiplication of chondrocytes of cartilage.
  • IGF-1 also has stimulatory effects on osteoblast and chondrocyte activity to promote bone growth.

• Embryonic and Fetal Bone Formation

  • Chondrocytes in the primary center of ossification begin to grow (hypertrophy).