Skeleton System

Skeletal System

Includes bones, cartilages, ligaments, and connective tissues that connect and stabilize the body.

Functions of the Skeletal System

Structural support, mineral storage, blood cell production, protection of tissues, and function as levers.

Mineral Storage

98% of the calcium in the body is deposited in the skeleton.

Blood Cell Production

The skeletal system produces blood cells.

Osseous Tissue

Another name for bone.

Bone Matrix

Solid and sturdy due to the deposition of calcium salts.

Calcium Phosphate Crystals

Constitute almost two-thirds of the weight of bone and can withstand compression.

Collagen Fibers

Account for the remaining one-third of bone weight; tough and flexible.

Osteocytes

Mature bone cells found in Haversian systems.

Osteoblasts

Cells that synthesize organic components of the bone matrix, responsible for bone building.

Osteoclasts

Cells that break down the bone matrix and regulate calcium and phosphate ions.

Osteogenesis

The production of new bone by osteoblasts.

Osteolysis

The breakdown of bone matrix by osteoclasts.

Osteoprogenitor Cells

Mesenchymal cells that can differentiate into osteoblasts; important for fracture repair.

Compact Bone

Dense bone that forms the walls of the marrow cavity.

Spongy Bone

Cancellous bone with no osteons, consisting of trabeculae.

Haversian System

The basic functional unit of compact bone.

Yellow Marrow

Dominated by adipocytes, found in the marrow cavity of bones.

Red Marrow

Dominated by blood cells, found in the marrow cavity.

Trabeculae

Struts or plates that form an open branching network in spongy bone.

Diaphysis

The long tubular portion of a long bone made of compact bone.

Epiphysis

The ends of a long bone, typically where articulation points are located.

Periosteum

A layer of connective tissue that surrounds bones.

Functions of the Periosteum

Isolates bone, provides a route for circulatory and nervous supply, and participates in bone growth and repair.

Endosteum

A thin vascular membrane that lines the inner surface of all bones.

Osteon

A structural unit of compact bone, consisting of a central canal surrounded by concentric rings.

Bone Mineralization

The process of deposition of minerals, especially calcium, in bone.

Bone Remodeling

The process of bone resorption and formation to maintain bone strength.

Fracture Repair

The process involving osteoprogenitor cells and osteoblasts to mend broken bones.

Articulation Points

Joints located at the ends of bones, typically where epiphyses are found.

Tendon Integration

Fibers from tendons become part of the structure of the bone.

Calcium Regulation

Managed by osteoblasts and osteoclasts to maintain appropriate levels in body fluids.

Mechanical Stress on Bone

Compact bone thickens in response to stresses arriving from limited direction.

Bone Weight Reduction

Spongy bone's lighter structure reduces overall skeleton weight for easier movement.

Haversian Canal

The central channel in the osteon that contains blood vessels and nerves.

Fibrous Periosteum

The outer layer of the periosteum, made of dense connective tissue.

Cellular Periosteum

The inner layer of the periosteum that is active in bone growth and repair.

Osteoid

The organic component of the bone matrix synthesized by osteoblasts.

Balance of Osteoblast and Osteoclast Activity

Critical for maintaining bone strength; imbalance leads to weaker bones.

Compression Strength of Bone

Bone’s ability to withstand forces that push it together.

Flexibility of Bone

The property that allows bone to bend and absorb shock.

Bone Fractures

Occur when the osteoclast activity exceeds osteoblast activity.

Mineral Components of Bone

Mainly consist of calcium and phosphorus, providing strength.

Bone Healing Phases

Involves inflammation, repair, and remodeling.

Hydroxyapatite

A form of calcium phosphate found in the bone that contributes to its hardness.