The functions of the skeletal system include mineral storage, energy storage, blood cell production and endocrine regulation. The skeleton provides support for muscles, allows for movement and protects the organs.
The skeletal system is made of the axial skeleton and the appendicular skeleton. The axial skeleton is made of 80 bones and consists of the rib cage, vertebral column and the skull. It is responsible for maintaining the upright posture of humans.
The appendicular skeleton is made of 126 bones and is formed by pectoral girdles, the upper limbs, the pelvis and the lower limbs. It makes possible movements such as walking and running. It also protects major organs responsible for reproduction, digestion and excretion.
Human infants are born with between 270 and 300 bones; however, as children develop the bones fuse together, and the number of bones decreases to 206. The human skeleton has a network of tendons, ligaments and cartilage that connect the bones. All the bones in the body are connected to each other, and the places where the bones attach to one another are called joints. The end of each bone is covered by a tough flexible connective tissue called cartilage. The bones are held together by fibrous bands called ligaments.