Bone+cells,+p9

Osseous Tissue/Bone
 * Bone is a connective tissue
 * Relatively few, spread out through the bone
 * Abundant matrix ( water, collagen, mineral salts)

Calcification
 * Deposition of mineral salts in a framework of collagen fiber in which the tissue hardens

Bones Are Hard Yet Flexible
 * Hardness- provided by crystallized mineral salts
 * Flexibility- provided by collagen fibers (resistant to being stretched or torn)

Types Of Cells In Bone Tissue 1. Osteoblasts 2. Osteocytes 3. Osteoprogenitor 4. Osteoclasts
 * Bone building cells
 * They create and secrete collagen and other materials needed to build the matrix
 * Mature bone cells
 * Maintains metabolism of the bone
 * NO CELL DIVISION.
 * "Bone stem cell"
 * Found in the periosteum
 * Undergo cell division differentiate into osteoblasts
 * Large cell formed from the fusion of 10-20 monocytes
 * Concentrated in the endosteum

Compact Bone Tissue
 * Contains few spaces
 * Forms the exterior layer of all bones and the diaphysis of long bones
 * Provides protection and support
 * Resists stress produced bu weight and movement

Osteon
 * The basic unit of compact bone

Perforated Canals
 * Transverse canals that through compact bone
 * Carry blood vessels, lymphatic vessels, and nerves from the periosteum

Central (Haverian) Canal
 * Runs longitudinally through the bone
 * It is the center of the osteon
 * Contains blood vessels and nerves

Concentric Lamellae
 * Rings of hard calcified matrix surrounding the central canal

Lacunae
 * Means 'Little Lake'
 * Small spaces in between lamellae
 * contains osteons

Canaliculi
 * Minute canals that that radiate off the lacunae in all directions
 * Contains projections of the osteocytes
 * Connect lacunae creating a network throughout the compact bone to provide nutrients and oxygen to all the osteocytes and to get rid of waste

Spongy Bone
 * Does not contain osteons
 * Made of trabeculae
 * Trabeculae contain osteocytes within lacunae connected by canaliculi
 * Spongy tissue makes up most of flat, short and irregular bone
 * Forms most of the epiphyses of long bones
 * Spongy tissue is light, reducing the weight of the skeletal system
 * Red bone marrow is found in the spaces between trabeculae