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Skeleton Systems

Provide a discussion of the normal anatomy of endochondral versus intramembranous bone growth
Describe the pathological (disease) processes involved in achondroplasia, and answer this question: Why do individuals with achondroplasia have a normal sized head but abnormally proportioned limbs?
Discuss how bone remodels throughout life and the healing process of a fracture.

Resources:
Bobick, J and Balaban, N. "Skeletal System." Handy Anatomy Answer Book. Visible Ink Press. MI, USA. 2008. eISBN: 9781578592326

Brooks, Arthur. "Muscular and Skeletal System." Systems of Our Body. Pgs. 87-96. Global Media. Delhi, India. 2007. eISBN: 9788189940829

Hall, BK. Bones and Cartilage: Developmental Skeletal Biology. Chapters 1-3. Academic Press, Jordan Hill, GBR. 2005. eISBN: 9780080454153

Solution Preview

Skeletal System(c)
Provide a discussion of the normal anatomy of endochondral versus intramembranous bone growth
Describe the pathological (disease) processes involved in achondroplasia, and answer this question: Why do individuals with achondroplasia have a normal sized head but abnormally proportioned limbs?

Discuss how bone remodels throughout life and the healing process of a fracture.

1. Provide a discussion of the normal anatomy of endochondral versus intramembranous bone growth

Ossification is the process by which bone forms. Sometime it is referred to osteogenesis. The human embry is composed of loose mesenchymal cells that shaped like bones and are the sites where ossification occurs. There are two methods of bone formation and growth. Both methods involve the gradual destruction of original connective tissue and the replacement of a preexisting connective tissue with bone. The first type of ossification or bone formation is called intramembrane ossification, in which bone forms directly within mesenchyme arranged in sheetlike layers that resemble membranes. These type of bones formed are flat bones and short bones. An example is the flat bones of the skull and mandible (lower jaw) are formed this way. There process begins with 4 steps: (1) Development of ossification center. Mesenchymal cells cluster together and differentiate into osteogenic cells and into osteoblasts in a primary ossification center. Osteoblasts secrete organic extracellulare matrix of bone to surround the bone. (2) Calcification: The next step is that the secretion of extracellular matrix stops and the cells are now called osteocytes, which lie in lacunae and extend their narrow cytoplasmic processes into canaliculi that radiate in all directions. The calcium and other mineral salts are deposited and the extracellular matrix hardens or calcifies within a few days. (3) Formation of trabeculae. When the bone extracellular matrix hardens, it develops into trabeculae that fuse with one another to form spongy bone and blood vessels grow into the spaces between the trabeculae. (4) Development of the periosteum. The mesenchyme condenses and develops into the periosteum. A thin layer of compact bone replaces the surface layers of the spongy bone. As the bone is transformed into its adult size and shape, much of the newy formed bone is destroyed and reformed.

Intramembranous ossification

The second method of bone formation is endochondral ossification that involve bone forms within hyaline cartilage that develops from the mesenchyme. This type of bone formation is responsible for formation of long and short bones. This process primarily involve the replacement of cartilage by bone, and almost most bone of the body are formed in this way. It involves several ...

Solution Summary

Bone is made up of several tissues. Bone tissue is a dynamic tissue engage in process of remodeling, the construction of new bone and breaking down of old bones. The entire framework of bones and their cartilages is known as the skeletal system. We will explore the process of the formation of bone, bones diseases, and the remodeling of bone fractures.

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