Bone Tissue and the Skeletal System: Structure, Function, and Classification

Bone Tissue and the Skeletal System

Functions of the Skeletal System

The skeletal system is essential for multiple physiological and structural roles in the human body. Its functions include:

• Support: Provides a rigid framework that supports the body and maintains its shape.

• Facilitation of Movement: Acts as levers and points of attachment for muscles, enabling movement.

• Protection: Shields vital internal organs (e.g., skull protects the brain, rib cage protects the heart and lungs).

• Hematopoiesis: Produces blood cells in the red bone marrow, a process known as hematopoiesis.

• Storage: Stores and releases minerals (such as calcium and phosphorus) and fats (in yellow bone marrow).

Classification of Bones

Bones are classified based on their shapes and structures, which relate to their functions.

Major Bone Types

• Long Bones: Cylindrical in shape, longer than they are wide. Examples: humerus, femur, metacarpals, metatarsals.

• Short Bones: Cube-like in shape, approximately equal in length, width, and thickness. Examples: carpals (wrist bones), tarsals (ankle bones).

• Flat Bones: Thin, often curved bones. Examples: scapulae, cranial (skull) bones, sternum.

Additional Bone Classifications

• Irregular Bones: Complex shapes that do not fit into other categories. Examples: vertebrae, many facial bones.

• Sesamoid Bones: Small, round bones shaped like a sesame seed, typically found embedded within tendons. Examples: patella (kneecap), variable number in tendons.

Bone Anatomy Terms

Understanding the structure of bones is crucial for comprehending their function and growth.

Key Anatomical Features

• Diaphysis: The tubular shaft of a long bone.

• Epiphysis: The proximal and distal ends of a long bone.

• Metaphysis: The narrow area between the diaphysis and epiphysis at each end of the bone; contains the growth plate in growing bones.

• Medullary Cavity: The hollow region within the diaphysis, filled with yellow marrow in adults (site of fat storage).

Continued Bony Anatomy Terms

• Epiphyseal Plate: Area of bone growth in length (also called the growth plate), located in the metaphysis of growing bones.

• Epiphyseal Line: The remnant of the epiphyseal plate after bone growth in length has ceased (adulthood).

• Endosteum: Lining of the medullary cavity; site of bone growth, repair, and remodeling.

• Periosteum: A fibrous membrane covering the outer surface of bone; serves as a site for ligament and tendon attachment and contains cells important for bone growth and repair.

Additional info: These notes are based on standard anatomical terminology and the provided slides. For a more comprehensive understanding, students should refer to textbook diagrams and histological images of bone tissue.