Skeleton

Humans are vertebrates, which are animals that have a backbone. The sturdy scaffolding of bones and cartilage that is found inside vertebrates is called a skeleton. The adult human skeleton has about 206 bones, some of which are named in Figure.
The skeletal system is made up of bones, cartilage, and ligaments.
Bones are not only the hard mineral part as the remains that you might see in a museum. Living bones are full of life. They contain nerves, blood vessels and many different types of tissues
Cartilage is found at the end of bones and is made of tough protein fibers called collagen. Cartilage creates smooth surfaces for the movement of bones that are next to each other, like the bones of the knee.
Ligaments are made of tough protein fibers and connect bones to each other.
Functions of Bones
Your skeletal system gives shape and form to your body, but it is also important in other homeostatic functions. The main functions of the skeletal system are:

• Support The skeleton supports the body against the pull of gravity. The large bones of the lower limbs support the trunk when standing.
• Protection The skeleton provides a framework that supports and protects the soft organs of the body. For example, the skull surrounds the brain to protect it from injury. The bones of the rib cage help protect the heart and lungs.
• Movement Bones work together with muscles as simple mechanical lever systems to move the body.
• Making Blood Cells Blood cells are made mostly inside certain types of bones.
• Storage Bones store calcium. They contain more calcium than any other organ does. Calcium is released by the bones when blood levels of calcium drop too low. The mineral phosphorus is also stored in bones.

As in other units in this link Kidshealth you can read and listen information about this subject, and finally a video with a reviw of all about skeleton.