The skeletal system is composed of 206 bones in the adult human body, along with cartilages, ligaments, and tendons. The bones provide structural support, protect vital organs, and facilitate movement in conjunction with the muscles. Divided into the axial skeleton (skull, vertebral column, and rib cage) and the appendicular skeleton (limbs and the shoulder and pelvic girdles), the skeletal system also includes joints that allow flexibility and body movement. Cartilages reduce friction at joints, while ligaments connect bones, and tendons attach muscles to bones.

The muscular system consists of over 600 muscles that enable movement, maintain posture, and produce heat. There are three main types of muscles: skeletal, cardiac, and smooth. Skeletal muscles, which are voluntarily controlled, are attached to bones and are responsible for movements such as walking and lifting objects. Cardiac muscles, found only in the heart, contract rhythmically to pump blood, while smooth muscles, located in internal organs, perform involuntary movements. Working in opposing pairs, skeletal muscles alternately contract and relax to create motion, exemplifying the collaboration between the skeletal and muscular systems for mobility and stability in the human body.