What are the zones of ossification?
Zone of ossification: Osteoblasts deposit bone matrix on the exposed plates of calcified cartilage. Zone of resorption: Osteoclasts absorb the oldest ends of the bone spicules. Note the high vascular density in this area: one capillary loop for each chondrocytic column.
What are the 4 zones of the epiphyseal plate?
Terms in this set (4)
- Proliferation Zone. Zone 1. Cartilage cells undergo mitosis.
- Hypertrophic Zone. Zone 2. Older cartilage cells enlarge.
- Calcification Zone. Zone 3. Matrix becomes calcified; cartilage cells die; matrix begins deteriorating.
- Ossification Zone. Zone 4. New bone formation is occurring.
What are the four steps of ossification?
Intramembranous Ossification Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form.
What are the zones of endochondral ossification?
Endochondral ossification is the process by which growing cartilage is systematically replaced by bone to form the growing skeleton. This process occurs at three main sites: the physis, the epiphysis, and the cuboidal bones of the carpus and tarsus.
What are the zones of the physis?
The physis itself is divided into three ma- jor zones: the reserve zone, the proliferative zone, and the hypertrophic zone (Fig. 3). Each one of these zones has a distinct histology directly related to its function.
What are the four zones of bone growth?
Make sure you can identify articular cartilage, the epiphysis, the diaphysis, primary and secondary centres of ossification, and the epiphyseal (or growth) plate of cartilage lying between these centres of ossification.To help you recognise the zones in the growth plate, here is a diagram of the different zones, found …
Where does the primary ossification center form?
diaphyseal
Primary ossification center forms in the diaphyseal region of the periosteum called the periosteal collar. Secondary ossification centers develop in the epiphyseal region after birth.
What is primary ossification Centre?
A primary ossification center is the first area of a bone to start ossifying. It usually appears during prenatal development in the central part of each developing bone. In long bones the primary centers occur in the diaphysis/shaft and in irregular bones the primary centers occur usually in the body of the bone.
What is the primary ossification center in endochondral ossification?
Primary center of ossification The perichondrium becomes the periosteum. The periosteum contains a layer of undifferentiated cells (osteoprogenitor cells) which later become osteoblasts. The osteoblasts secrete osteoid against the shaft of the cartilage model (Appositional Growth).
Where do secondary ossification centers occur?
Secondary ossification centers appear in the epiphyses, which then ossifies. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages. The formation of new bone along an existing bone surface.
What is a type 4 fracture?
Similar to a type III fracture, a type IV fracture is an intra-articular fracture; thus, it can result in chronic disability. By interfering with the growing layer of cartilage cells, these fractures can cause premature focal fusion of the involved bone. Therefore, these injuries can cause deformity of the joint.
When does the secondary center of ossification appear?
Secondary center of ossification 1 They usually appear after birth from which the ends of the developing long bone ossify. 2 They form the epiphyses of the long bones. 3 In case of femur the secondary center of ossification for the lower end appears just before birth.
What are the four steps of intramembranous ossification?
Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes.
Which is a stage of endochondral ossification?
Stages of Endochondral Ossification Formation of bone collar Cavitation of the hyaline cartilage Invasion of internal cavities by the periosteal bud, and spongy bone formation Formation of the medullary cavity; appearance of secondary ossification centers in the epiphyses Ossification of the epiphyses, with hyaline
How many centers of ossification does the clavicle have?
Clavicle has 2 primary centers of ossification. 2. Secondary centres of ossification appear after birth and can be can be single or multiple.