Final answer:
The skeletal system includes both bony plates and softer structures like cartilage and ligaments. It is made up of 206 bones in adults and performs functions such as support, organ protection, and movement facilitation.
Step-by-step explanation:
The skeletal system is composed of bony plates which primarily include bones, but also cartilage and ligaments. For adults, the skeleton contains 206 bones, each made up of dense connective tissue mainly composed of collagen. These structures are hardened by the deposits of calcium and other mineral salts within their living tissues, making them rigid yet somewhat flexible to enable movement and support the body against gravity. The skeletal system has numerous functions such as providing support, shape, protecting internal organs, facilitating movement, producing blood cells, and storing minerals and fat.
Specifically, the axial skeleton consists of 80 bones which protect the brain, ears, heart, and lungs among other organs. This includes the skull, vertebral column, thoracic cage (comprised of ribs and sternum), as well as the ossicles in the middle ear and the hyoid bone in the throat. The appendicular skeleton includes the bones of the upper and lower limbs as well as those that anchor the limbs to the axial skeleton.