Human Physiology

Lesson 11 : Bone Structure

Structure of Typical Lone Bone

In longitudinal section, in a typical long bone following parts can be appreciated.

1. Compact Bone: is outermost rigid substance which is thickest in center and thin towards extremities. This provides strength to the bone.
2. Spongy Bone: is middle part made up of soft bony plates and spicules running in different directions intercrossing each other. Within these spicules lies a marrow space that encloses bone marrow tissue, the blood forming tissue.
3. Periosteum : is outermost membrane of bones and it is covered with cartilage. It has outer fibrous layer and inner cellular osteogenic layer.
4. Endosterm: is fibrous layer lining the medullary cavity and Haversian canal.
5. Marrow: is soft tissue occupied in spongy bone and medullary cavity. Red marrow contains various precursors of blood cells and yellow marrow chiefly contains fatty tissue.