Describe the internal structure of the bone.

Allocate a dense (compact) and spongy substance. The compact substance is developed in bones, which perform the function of support and movement, and consists of cylindrical plates inserted one into the other, through the channels of which blood vessels penetrate into the bone. The spongy substance is formed by plates located in the direction of the greatest loads, between which there is red bone marrow. Outside, the bone is covered by the periosteum, rich in blood vessels and nerves, and the articular surfaces are covered with cartilage.

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