CNamed Parts of an Individual Long Bone

(1) Shaft (diaphysis). The shaft is the central portion of a long bone. Here, the cortex is thickened as required by applied physical stresses.

(2) Ends (epiphyses). The ends of long bones are made up mainly of cancellous (spongy) bone tissue. An articular cartilage covers each area where a bone contacts another bone(s). This articular cartilage is made up of hyaline cartilage tissue and provides a smooth surface for motions.

d. Periosteum. The periosteum is a covering of the bone surface area not covered by articular cartilage. It has two layers--the innermost layer and the fibrous layer.

(1) The innermost layer, which lies against the outer surface of the bone, consists of bone-forming cells (osteoblasts). It is the osteogenic (bone-forming) layer.

(2) The outermost layer is a FCT (fibrous connective tissue) layer.

(3) The periosteum is well supplied with blood vessels and sensory-type nervous tissue.

e. Blood Supply of an Individual Bone. A system of blood vessels enters and spreads out through the periosteum. Additional blood vessels, called "nutrient vessels," penetrate the cortex of the bone and spread out through the marrow. The passageways for penetration of these vessels are called the nutrient canals.

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