Skeletal System

The skeletal system performs several crucial functions, including providing movement, support for the body, storage of minerals, manufacturing of blood cells, and protection of vital organs.

Bones are classified based on their shape. One common type is the long bone, exemplified by the femur in your leg.

The ends of a long bone are called epiphyses. They are wider than the shaft and covered with articular cartilage, which helps reduce friction at joints.

The shaft of a long bone is called the diaphysis. It's the long, cylindrical main part of the bone.

The area between the epiphysis and diaphysis is called the metaphysis. It's where bone growth occurs.

Spongy bone, also called cancellous bone, is found in the epiphysis. It's porous and lighter than compact bone.

The epiphyseal line, previously the epiphyseal plate, is a line of cartilage where bone growth occurs. After growth is complete, it becomes a solid line.

The medullary cavity is the hollow space inside the diaphysis of a long bone. It contains yellow bone marrow.

The periosteum is the fibrous membrane that covers the bone. It provides nourishment to the bone, helps repair bone fractures, and serves as a point of attachment for muscles and tendons.

Fibrous joints are immovable joints held together by fibrous connective tissue. They provide strong support and stability, but don't allow for movement.

Cartilaginous joints are immovable joints held together by cartilage. They provide cushioning and flexibility, but limited movement.

Synovial joints are movable joints filled with synovial fluid to reduce friction. They allow for a wide range of motion.

The spinal column provides support for the body, protects the spinal cord, and allows for flexibility and movement.

The spinal column is divided into three main sections: cervical, thoracic, and lumbar.

A type of synovial joint where a rounded bone head fits into a cup-shaped socket, allowing for wide-ranging movement in multiple planes.

A type of synovial joint that allows movement only in one plane, like opening and closing a door.

A type of synovial joint where the articular surfaces are shaped like a saddle and rider, allowing for movement in two planes.

A type of synovial joint that allows for rotation around a central axis.

A type of synovial joint where flat, bony surfaces slide over each other, providing limited movement.

Ossification is the process where cartilage is replaced by bone through the deposition of calcium and minerals by osteoblasts.

Osteoblasts are bone-building cells that secrete mineral deposits to replace cartilage during ossification. They then mature into osteocytes.

The first stage of bone repair is the formation of a hematoma, which is a blood clot that fills the gap between the broken bone ends.

Osteoclasts are bone-resorbing cells that break down bone tissue, creating space for the formation of new bone or for bone marrow.

Osteoid is the organic part of bone, made of collagen, which gives it flexibility. Mineral salts are the inorganic part, mainly calcium salts, which provide hardness.