Reference: Skeletal System http://www.livescience.com/22537-skeletal-system.html
Skeletal System: Facts, Function & Diseases
Kim Ann Zimmermann, LiveScience Contributor | August 20, 2012 04:37pm ET
The adult human skeletal system consists of 206 bones, as well as a network of tendons, ligaments and cartilage that connects them. The skeletal system performs vital functions — support, movement, protection, blood cell production, calcium storage and endocrine regulation — that enable us to move through our daily lives.
Animals with internal skeletons made of bone, called vertebrates, are actually the minority, as 98 percent of all animals are invertebrates, meaning they do not have internal skeletons or backbones. Human infants are born with 300 to 350 bones, some of which fuse together as the body develops. By the time most children reach the age of 9 they have 206 bones. The skeletons of adult males and females have some variation, primarily to accommodate childbirth. The female pelvis is flatter, more rounded and proportionally larger. A male's pelvis is about 90 degrees or less of angle, whereas a female's is 100 degrees or more.
The skeleton is composed of fibrous and mineralized connective tissues that give it firmness and flexibility. It consists of bone, cartilage, tendons, joints, and ligaments.
* Bone - a type of mineralized connective tissue that contains collagen and calcium phosphate, a mineral crystal. Calcium phosphate gives bone its firmness. Bone tissue may be compact or spongy. Bones provide support and protection for body organs. * Cartilage - a form of fibrous connective tissue that is composed of closely packed collagenous fibers in a rubbery gelatinous substance called chondrin. Cartilage provides flexible support for certain structures in adult humans including the nose, trachea, and ears.
* · Tendon - a fibrous band of connective tissue that is bonded to bone and connects bone to bone.
* · Ligament - a fibrous band of connective tissue that joins bones and other connective tissues together at joints.
* · Joint - a site where two or more bones or other skeletal components are joined together.
Label the Bones Game: http://www.abcya.com/skeletal_system.htm