When humans are born, they have over 300 bones; however, many are comprised of soft cartilage. Because human skeleton is an endoskeleton (bones are inside the body), the bones grow with the human body. Consequently, as babies develop, several of these bones begin to join together. As a result, the adult human skeleton has 206 bones. The skeleton has several functions: it protects internal organs and soft tissue; and it supports the body. Bones come in many shapes and sizes. The largest bone is the femur, or thigh bone. The smallest bone, the stapes, or also called the stirrup, is located inside the ear. The skeletons of males and females are somewhat different. Females have a wider pelvis and males have longer, thicker arm and leg bones.
The axial skeleton and the appendicular skeleton are the two main segments of the human skeleton. The axial skeleton protects the brain, the spinal cord, and organs in the thorax including the lungs, heart and large blood vessels. It also supports the neck and head.
The arm, leg and pelvic bones make up the appendicular skeleton. Bones also have several small holes and canals so blood vessels can transport blood throughout the skeletal system. These blood vessels carry calcium and other minerals and nutrients through the body. This is done with the help of three types of bone cells: osteoblasts, osteocytes and osteoclasts. Osteoblasts build bone and produce collagen and hard calcium.
Osteocytes remove and replace calcium which helps to maintain the hard bone tissue. Osteoclasts destroy bone cells by breaking down bone matter to release phosphate and calcium into the blood.
Joints connect bones to each other and help the body to bend and move flexibly. Some joints such as hinged joints can be found in the fingers and toes. Ball- and- socket joints are located in the hips and shoulders. The joints in skull are called fixed joints.
Bones are an integral component of the human body. Without the 206 bones that make up the human skeletal system, the human body would be unable to move, lack protection for its vital organs, and support for its muscles.
Posted 3808 day ago