The Skeletal System
Prepare a 2 page paper in which you: 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. NOTE: This assignment will require you to engage in independent research to learn about achondroplasia and bone growth and repair throughout life. I have provided some resources for you on the ebrary bookshelf to get you started. Begin your research by looking through the following books: Bones and Cartilage: Developemental Skeletal Biology, Growth Plate, and Human Growth and Development. Look up terms that you do not know, take notes, and assemble these notes INTO YOUR OWN WORDS. Copied text will receive a failing grade. Assignment Expectations Format Remember that all of your work should be prepared using appropriate format. This link from your course syllabus page will help reinforce formatting expectations: http://www(dot)trident(dot)edu/files/Well-Written-Paper.pdf Scholarly Content Your SLP and your case assignments are considered scholarly works. Your final work should include a MINIMUM of 10 peer reviewed (scholarly) sources. This does not mean that you must place 10 peer reviewed sources in each module of your Case/SLP. I anticipate that the nature of the questions which must be answered in this project will result in the accumulation of more than 10 references, but 10 is the minimum number. This means by the end of module 5, I should be able to go back and count AT A MINIMUM a total of 10 scholarly-peer reviewed publications in all of your submitted papers. If you are uncertain what a peer reviewed (scholarly) source is, go to http://www(dot)csuchico(dot)edu/lins/handouts/scholarly.pdf . Please keep in mind that you should not use sources such as “Answers.com” or “Wikipedia” or “Wikianswers”. None of these are scholarly sources and they can be “modified” by any registered user which makes it unreliable. It could very well be that those who modify subjects in Wikipedia have a very good knowledge of the subject, however, since we have no way of knowing their credentials or intentions, we cannot guarantee that the source is reliable. It is a good place to start, but should not be used as factual in graduate writing. For graduate study, be sure to stick to peer reviewed journals and scientific sources. If you are having trouble finding a place to begin, try the References, or Bibliography, section at the end of the chapters in your assigned readings or ebrary books. The books on your ebrary shelf are all scholarly references as well. The following site will help: http://www(dot)csuchico(dot)edu/lins/handouts/scholarly.html
Bones
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Bone development can take place embryonic and in other cases postembryonic. The former is the stage of development that takes place within the womb, where cells from precursors that are not specific differentiate and form organs and tissues. The latter kind of development of the bones is associated with growth outside the womb, such as is the case with growing taller at puberty. The embryonic form of development is also associated with two types of development namely; intramembranous and endochondral ossification (Tamarkin, 2011).
The intremembranous bones are formed from membranes/connective tissues that develop where later on bones form. Such is the case of the flat bones like the skull. The osteoblasts in the sheets of membrane lay out the extracellular matrix that then forms the bones which are spongy. The osteoblasts which are now trapped within the hard matrix are referred to as the osteocytes. The connective tissues/periosteum produces the osteocytes that accumulate over the spongy bone.
The endochondral ossification process is basically the replacement of the hyaline cartilage with bone. The cartilage works as a model, which will guide the process of the bone formation. The periostuem are still the ones that produce the osteocytes in the case. As the chondrocytes begin to die, they swell, starting at the centre of the diaphysis and then proceeds to the epiphysis. As the osteocytes are trapped inside, they produce the extracellular matrix that is a hard material forming the spongy bone. When the osteocytes cannot access the spongy matrix, they secrete compact material on the outside.
During the bone formation, there may be sporadic mutations, where the patients may result in dwarfism (Radiopaedia, 2013). As a result of the mutations, there is cartilage formation inhibition, which interferes with the normal endochondral bone formation. Bones that normally have fast growth and fewer plates are most affected, such as the femurs, humerus and the long bones of the arms. The trunk on the other hand has many plates thus is not affected. All the other bones of the clavicle, skull and face are not affected as they form through the intramembranous ossification, which explains why the dwarfs have a normal...