长久以来，人类骨骼被认为是依照其骨质经受的压力来不断构建和消灭细胞。

It has long been known that the human skeleton constantly constructs and destroys cells, according to the stresses that its bones experience.

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每七年，健康的人体的骨骼细胞会更新一遍。

Every seven years, a healthy human body completely replaces every single bone cell.

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有些细胞源自骨骼，称为造骨细胞，在需要时可以构造骨骼。

Some cells produced in bone, called osteoblasts, build bone where it is needed.

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We have other ways of protecting; many of our cells are inside our body protected by specialized cells of our skeletal system.

人类有其它的保护机制,我们体内的细胞受,特化的骨骼细胞保护

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