The document discusses key facts about the skeletal, muscular, and integumentary systems of the human body. It provides information such as:
- The skeletal system contains 206 bones that are made hard through minerals. The compact bone and cartilage are important parts. There are several types of joints including immovable joints.
- The body contains around 600 muscles that are mostly skeletal muscles. Cardiac muscles contract faster than other muscle types.
- The integumentary system includes the skin, which contains melanin for color and millions of sweat glands. Vitamin D helps absorb calcium.