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GE 345: Week 8Skeletal System |
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[ Bone ]
[ Skeleton ]
[ Terms ]
The Skeletal SystemThe skeletal system consists of bone and cartilage, which provide the body's framework. Bones are important for movement, support, protection, and mineral storage.
When considered as a whole, the system provides a balance of stability and freedom of movement, allowing the individual to constantly adjust to shifting of the base of support and center of gravity. Basic bone structures include: long bones, such as the femur and humerus, which are basically long tubes with a medullary (marrow) cavity along the middle; short bones such as the digits; flat bones such as the scapulae; and irregular bones such as the carpal and tarsal bones. The bone itself may be compact or cancellous (spongy), or some combination of the two. Bone is constantly being absorbed (broken down) and formed:
In children, bone formation occurs at a higher rate. In adults, these rates are about the same. In the elderly, bone deposition declines. Typically, bone adjusts its strength porportionally to its stresses. It thickens when subjected to heavy loads, and its shape can be rearranged for proper support. It also develops new matrices as the old matrices degenerate. Bone deposition is proportional to compressional loads to which the bone is subjected. When a bone breaks, many new osteoblasts are created to form a new bone matrix.
[ Bone ]
[ Skeleton ]
[ Terms ]
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