Bio Lab Skeletal System

Types of Bones and Their Functions

Long Bones

•  Function: Support body weight, facilitate movement, and produce blood cells.

•  Examples:  Femur, humerus, tibia, radius.

Short Bones

•  Function: Absorb shock and distribute force.

•  Examples:  Carpals (wrist bones), tarsals (ankle bones).

Flat Bones

•  Function: Protect organs and provide muscle attachment.

•  Examples:  Skull bones, ribs, sternum, scapula.

Irregular Bones

•  Function: Vary in function based on shape (protection, support, movement).

•  Examples:  Vertebrae, pelvis, some skull bones.

Sesamoid Bones

•  Function: Reduce friction and improve muscle efficiency.

•  Examples:  Patella (kneecap), pisiform (wrist).

Key Bone Features

Foramen – A hole in a bone that allows nerves and blood vessels to pass through.

Example:  Foramen magnum in the skull.

Fossa – A shallow depression in a bone, often serving as an articulation site.

Example:  Glenoid fossa of the scapula.

Meatus – A canal-like passageway in a bone.

Example:  External acoustic meatus (ear canal).

Articulation Site – The place where two bones meet to form a joint.

Example:  Knee joint, elbow joint.

Sutures – Immovable joints where skull bones fuse.

Example:  Coronal and sagittal sutures in the skull.

Bone Growth and Development

Fontanelles – Soft spots in a newborn’s skull that allow skull flexibility during birth and brain growth.

•  Ossify (harden) over time to form sutures.

Osteoblasts – Bone-forming cells that secrete  phosphate  and calcium to build bone.

Ossification Process – Mesenchymal stem cells receive signals ( BMPs, Wnt, FGFs) to become osteoblasts.

•  Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) – A mineral that gives bones their rigidity.• Osteocytes – Mature bone cells that maintain bone tissue and communicate with other bone cells through their dendritic processes.