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

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. It provides the framework for the body, enables movement, and protects vital organs.

• Support: The skeleton supports the body’s structure and maintains its shape.

• Facilitation of Movement: Bones act as levers and points of attachment for muscles, allowing movement.

• Protection: Bones protect internal organs, such as the brain (skull), heart and lungs (rib cage).

• Hematopoiesis: The production of blood cells occurs in the red bone marrow, a process called hematopoiesis.

• Storage: Bones store and release minerals (such as calcium and phosphorus) and fat.

Classification of Bones

Bones are classified according to their shapes and functions. This classification helps in understanding their roles and locations in the body.

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

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

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

Continuation of Bone Classification

• 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 bone anatomy is crucial for identifying bone structure and function.

• 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.

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

Continued Bony Anatomy Terms

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

• Epiphyseal Line: The visible line that remains after the epiphyseal plate has stopped growing in length after childhood.

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

• Periosteum: A fibrous membrane that covers the outer surface of bone; serves as a site for ligament and tendon attachment.

Additional info:

• Hematopoiesis is the process of blood cell formation, which occurs primarily in the red bone marrow found within certain bones.

• Yellow marrow is primarily composed of adipose tissue and serves as an energy reserve.

• Growth plates are critical during childhood and adolescence for longitudinal bone growth.