What are the main events of endochondral ossification?

Answer 1

Meschyme (embryonic connective tissue) develops into a body of hyaline cartilage, covered with fibrous perichondrium, in the location of a future bone. For time, the perichondrium produces chondrocytes and the cartilage model growth in thickness.

Answer 2

1. The skeleton is formed by hyline cartilage model.

2. The outer layer covering the bone begins to form around the outside.

3. Osteoblast form bone beneath the periosteum. This is called a bone collar and this will become compact bone.

4. At the center of the diaphysis the cartilage cells die creating a cavity.

5. Blood vessels grow into this cavity from the periosteum and deliver osteoblast to the area.

6. Ossification begins around the medullar cavity, this is spongy bone.

7. The same process now occurs in the epiphyses. Steps 4-6.

8. All cartilage is ossified except the areas between the diaphysis and epiphysis. This area is the epiphyseal plate also known as the growth plate. The cartilage cells here continues to divide and ossification occurs at the outer borders allow for longitudinal growth.

9. Cartilage also remains at the ends of the bone, this is the articular cartilage at the joint

Answer 3

Development of the cartilage model: mesenchymal cells form shape of the bone and develop into chondroblasts that form hyaline cartilage model.

2.Growth of the cartilage model: Chondroblast become chondrocytes. Some

chondrocytes hypertrophy-burst; causing a pH change which initiates calcification

of cartilage model. Growth in length: chondroblasts go through interstitial growth.

Growth in thickness: new chondroblasts are produced by perichondrium.

3.Development of the primary ossification center: nutrient artery penetration in

the middle diaphysis induces perichondrium cells in the perichondrium to

differentiate into osteoblasts; later becomes periosteum. Osteoblasts deposit

spongy bone; primary ossification spreads from out to inward and towards both

ends of cartilage model.

4.Development of marrow cavity: Osteoclast breaks down some of the newly

formed spongy bone trabeculae leaving a marrow cavity and osteoblasts replace

spongy bone with compact bone in the diaphysis.

5.Development of the secondary ossification center: Blood vessels penetrate the epiphyses, allowing ossification to start in the middle of the epiphysis and work outwards in both directions.6.Formation of the articular cartilage and epiphyseal plate: Hyaline

cartilage becomes the articular cartilage and later becomes the epiphyseal plate

Answer 4

a bone collar forms around the diaphysis of the hyaline cartilage model. the cartilage in the center of the diaphysis calcifies and then cavitates. the periosteal bud invades the internal cavities and spongy bone forms. the diaphysis elongates and a medullary cavity forms. the epiphyses ossify.

Answer 5

Endochondral Ossification: bones begin as hyaline cartilage model. This happens in most
bones of the skeleton and these are called endochondral bones.The hyaline cartilage model has a primary ossification center and secondary ossification centers.This all begins in the second month of development when breakdown of hyaline cartilage occurs.
The Stages of Endochondral Ossification are:
1. Formation of what is called a bone collar
2. Cavities or holes in the hyaline cartilage
3. Invasion of internal cavities by the periosteal bud, and then spongy bone formation.
4. Formation of the medullary (middle cavity); appearance of secondary ossification centers in the epiphyses (ends).
5. Ossification of the epiphyses, with hyaline cartilage remaining only in the epiphyseal plates (for growth).

Answer 6

the formation of bone from pre-existing hyaline cartilage models

Answer 7

8 weeks foetal development

Answer 8

Hyaline cartilage