Lab Four: Skeletal Tissues
This week, we are examining tissues of the skeletal system. Specifically, we will investigate the process by which the long bone of the upper arm, the humerus, grows and lengthens in our patient, an 8-year old boy. Then, we will compare this process of growth with the process of healing and repair when this same patient sustains a distal end greenstick fracture of the humerus at his weekly gymnastics practice! Your assignment, which is worth 30 points, is to write a one to two page essay discussing the development and growth of a long bone, such as the humerus. Then, assume this bone has sustained the injury described above, and describe the process by which this injury is repaired. Be comprehensive! Be creative! Please use appropriate citation in APA format where appropriate. Begin your assignment below:
Bones grow in three stages during life. The bone starts growing in the embryo at around 8 weeks. Ossification is the word for the formation of bone. There are osteoblasts that help form the bone and osteoclasts that eat away at old bone. Bones start off as cartilage, but then is replaced by bone. Connective tissue forms a sheet where the bones are going to be. These connective tissue sheets are highly invested with blood vessels. Some of the cells in the connective tissue sheets differentiate into osteoblasts. These osteoblasts begin laying down the bone extracellular matrix, called spongy bone. These osteoblasts get trapped within the hard matrix and are then called osteocytes. As time goes more and more osteoblasts form from the connective tissue sheets. The connective tissue sheets, as they become major producers of osteocytes, are no longer called connective tissue sheets. They are now called the bone's periosteum. But the newer osteoblasts made by the periosteum cannot enter the spongy bone. So, they begin to accumulate on the edges of the spongy...
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