Description and definition of types of bone tissue, compact bone tissue and spongy bone tissue. Common to both are the presence of osteocytes and matrix. Matrix consists of non living calcium salts. The compact bone looks "solid" but is constructed of cylinders called osteons (see picture) containing bone matrix and osteocytes. Each osteon surrounds a central haversian canal containing blood vessels.Spongy bone appears spongy, contains bone marrow which produces erythrocytes, leukocytes and platelets. The classification of bone is observed from diagrams and photos. These are the long bones, the short bones, the flat bones, and the irregular bones. The major areas of location of each seen using a skeletal model.