The skeletal system consists of 206 bones that make up two divisions: the axial skeleton and appendicular skeleton. The axial skeleton includes the skull, vertebral column, and thorax, while the appendicular skeleton includes the upper and lower limbs. Bones can be classified by their shape as long, short, flat, or irregular. Each bone has specific structures including compact and spongy bone, periosteum, endosteum, and markings for muscle attachments. Bones provide structure, protection, movement, mineral storage, and blood cell production. They continuously remodel in response to hormones and mechanical stresses.