The skeletal system is a framework of bones and cartilage that provides structural support, protects vital organs, allows movement, stores minerals, and houses bone marrow for blood cell production.

Bones support the body, protect internal organs, facilitate movement by serving as levers for muscles, store minerals (like calcium and phosphorus), and produce blood cells in the bone marrow.

A joint is a point of connection between two or more bones, allowing movement and flexibility. Joints can be classified based on their structure and function, such as synovial, fibrous, and cartilaginous joints.

Cartilage is a flexible, semi-rigid connective tissue found in areas like joints, ears, and the nose. It provides cushioning, reduces friction in joints, and supports structures like the rib cage.

Ligaments are strong, flexible bands of connective tissue that connect bones to other bones at joints, providing stability and limiting excessive movement.

Tendons are fibrous connective tissues that connect muscles to bones, enabling the transfer of force from muscle contractions to bone movement.

Muscle contraction is the process in which muscle fibers shorten in response to a stimulus, resulting in movement. This process involves the interaction of actin and myosin filaments within muscle cells.

The axial skeleton consists of the skull, vertebral column, and rib cage. Its primary function is to protect the brain, spinal cord, and vital organs, while providing support for the body and attachment points for muscles.

The appendicular skeleton includes the limbs and their attachment points to the body, such as the shoulder girdle and pelvic girdle. It allows for movement and interaction with the environment.

Calcium is essential for maintaining bone density and strength. It is a major component of bone mineralization and helps prevent conditions like osteoporosis.