Growth Plates Research Paper

| - osteoblasts begin to replace the fibrocartilage splint with spongy and compact bone, forming a bulge that is initially wider than the original bony shaft

One of the key elements of regulating skeletal growth is the Osteoclasts. The Osteoclasts are responsible for initiating the bone remodeling cycle. Blood vessels and nerves are able to penetrate the bone once the chondrocytes die

Ossification is the process when the cartilage changes to bone as person grows. It fuses many of the body’s bones

Figure 1. Endochondral cartilage grown in the bioreactor for 3 weeks exhibited some characteristics of growth plate zones, matrix production, hypertrophy, reserve and proliferation, with evidence of vessel like structures necessary for ossification thus the endochondral cartilage differentiated into mature, matrix forming chondrocytes. This supports that they attained the stages of cartilage differentiation necessary for bone growth and healing.

There are numerous factors that contribute to the development of this horrible disease, but the most important factor is vitamin D deficiency. When the minerals in osteoid crystallize, they require adequate concentration of calcium and phosphate. When the concentration is not at the correct level, ossification does not proceed normally (Huether & McCance, 2008). Vitamin D regulates the absorption of calcium from the intestine. When there is a lack of vitamin D, the concentration of calcium begins to fall (Huether & McCance, 2008). The body begins to regulate this calcium drop by increases the amount of PTH synthesis and secretion (Huether & McCance, 2008). An increase of PTH causes a clearance of phosphate and without the correct levels of phosphate mineralization of the bones cannot proceed in the correct manor (Huether & McCance, 2008). The abnormality of bone growth can occur in spongy and compact bone (Mayo

Each year in the United States eight to forty children are born with malignant infantile osteopetrosis and one in every two hundred thousand people are affected by the adult form of osteopetrosis. Osteopetrosis is a rare genetic skeletal disorder in which there is an abnormal osteoclastic bone resorption resulting in patients who are more prone to fractures. This disorder “may be inherited as either a dominant or recessive trait and is marked by increased bone density, brittle bones, and, in some cases skeletal abnormalities” (NORD 2014). There are three major types of this condition. They are adult type autosomal dominant, malignant infantile type autosomal recessive, and the last is intermediate mild autosomal recessive.

While there has been some accord with respect to change of the proliferation capability of osteoblasts, some unfriendly impacts of FGF2 on the osteogenic separation and generalization have likewise been recognized.(Bosetti et al.) examined the striking of different FGFs (FGF2, FGF4, and FGF6) on the behavior of human-necessary osteoblasts. They examined that all FGFs activated in culture medium at 0.8 μM incited osteoblast enlargement yet stopped ALP motion and generalization. When it comes to Vitamin D, it was

Osteoblastogenesis takes place as a result of a number of signalling pathways such as the transforming growth factor-β (TGF-β), Wnt/β-catenin and mitrogen-activated protein kinase (MAPK) signalling. The TGF-β superfamily comprises of the TGF-βs and the bone morphogenetic proteins (BMPs), both of which play critical regulatory roles in bone tissue55,56. TGF-β presents in 3 isoforms namely TGF-β1, TGF-β2 and TGF-β3 with TGF-β1 in particular having a chemotactic effect on osteoblasts in order to promote bone formation55. TGF-β is initially expressed as an inactive complex which is made functional via one of three mechanisms: bond breaking between TGF-β and the latency associated peptide, degradation of the latency associated peptide or conformational change of the latency associated peptide itself55. Post-activation, the TGF-β binds to either type I or type II of the transmembrane serine/threonine receptors57.

It is when the cell osteoblasts are activated on the surface of the bone and creates layers of cells called osteoclasts which consume cartilage.

The beginnings of human history date back to over 20,000 years ago. However, the beginning of complex life on Earth began long before. Millions of years back in time, when the dinosaurs were still roaming the Earth, the planet consisted of only one supercontinent: Pangea. How do we know this? Alfred Wegener, a famous geographer, proposed a theory called Plate Tectonics that would explain why certain patterns of fossils of the same species were discovered on lands oceans away. This was due to continental drift, or the gradual movement of continents across the surface of the Earth over millions of years. If you fast-forward about few hundred million years to the beginning of the Holocene Epoch, you can see that humans have adapted away from hunting

Ossification is the transitional process through which cartilage and fibres form bone. The primary ossification centre is the initial site of bone formation in the shafts of long bone. At the primary ossification centre the osteoclast forms the bone marrow cavity and the osteoblast forms the bone. The secondary ossification centre occurs after the primary ossification centre is visible and ossification continues to occur at this site. The primary ossification centre occurs at the diaphysis and the secondary ossification centre occurs at the epiphysis. The primary ossification centre appears in week 8 of the intra uterine life and the secondary ossification centre appears during the first year of postnatal life. The diaphysis of the primary

Osteoblasts helpt the ossification of the bones and more in particularly the lengthening of the bones. Ossification is a development process taking place between 0 and 20 years to gradually harden and lengthen the bones. Young children have more flexible cartilage. Osteoblasts absorb calcium from the blood and lay it down as small plates in the cartilage in both directions. This causes the bone to

Articular cartilage is organized into four different layers/zones: superficial (tangential), middle (transitional), deep (radial), and calcified. The cellular structure of each layer is slightly different and corresponds to its role and type of force that it can withstand; the superficial layer has parallel alignment to withstand shear forces, the middle layer begins to resist compressive forces with a more oblique orientation, and the deep layer has a perpendicular alignment that largely resists compression. The calcified layer is where the cartilage connects to bone tissue, and is separated from the deep layer by the tidemark, which is a region of parallel-oriented fibers to reduce shear force. Since grading of chondral lesions (commonly on a Grade 0-4 scale) is based upon the depth of injury, it is important to understand these specialized

Bone is made up of two types of structure which are the compact bone and the spongy bone. Compact bone lies over spongy bone and makes up most of a bone’s diaphysis, it consist of compactly arranged osteons which is the Harvesian system. Compact bone able to protect, supports and resist stress. Spongy bone makes up most of the mass short, flat and irregular bones and is also found at the epiphyses of long bones. It stores marrow and provides some support. The size of the bone grow throughout childhood and adolescence as our body produces more bone than it loses. At some point in life, human will be at their peak bone mass density (BMD) which is the end of the bone growth. For normal human being, the BMD usually stays constant as the break down and regeneration of bone is equal. However, for certain people, the bone loses is more than the regeneration and production which then cause osteoporosis.

Overall, articular cartilage is a very dense structure, lacking blood vessels and nerves that are found in other tissues77. Chondrocytes are the cell types embedded within cartilage, and produce the structural proteins that form the ECM. The major components of the ECM are water, type II collagens, proteoglycans, aggrecan, and noncollagenous proteins such as fibronectins115,22. The resulting osmotic pressure created within the wet and dry components of the ECM work in harmony to support the mechanical forces applied to cartilage77. The water is retained in the ECM by aggrecan, the primary structural proteoglycan which is based on a long hyaluronic acid backbone with highly charged glycosaminoglycan (GAG) side chains, such as chondroitin sulfate (CS) and keratin sulfate (KS)26. Altogether, these components are what create the depth dependent layers of cartilage: the superficial zone, the middle zone, the deep zone, and the calcified zone (Figure