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Support and Protection
The skeletal system’s main function is to form a stable structure that maintains and guards the body’s organs and support the skeletal muscles. The bones of the axial skeleton serve as a hard case to preserve the internal organs—such as the heart and the brain—from injury caused by external forces. The bones of the appendicular skeleton produce relief and versatility at the joints and secure the muscles that move the limbs.
The bones of the skeletal system role as a connection point for the skeletal muscles of the body. Nearly each skeletal muscle works by drawing two or more bones either closer together or further apart. Joints act as pivot locations for the movement of the bones. The areas of each bone where muscles connect to the bone grow larger and stronger to support the additional force of the muscle. Also, the overall mass and thickness of the bone increase when it is under significant stress from lifting weights or-or supporting body weight.
The skeletal system stores several different types of essential substances to facilitate growth and restoration of the body. The skeletal system’s cells matrix acts as our calcium bank by storing and releasing calcium ions into the blood as needed. Certain minimum levels of calcium ions in the in the blood must be maintained to ensure effective function of the nervous and muscular systems. Bone cells are release osteocalcin, a hormone that helps control blood sugar and fat deposition. The yellow bone marrow within of our long hollow ones used to store energy in the composition of lipids. Lastly, red bone marrow collects some iron in the form of the molecule ferritin and multiples this iron to create hemoglobin in red blood cells.
Growth and Development
The skeleton starts to form early in fetal development as a flexible skeleton made of hyaline cartilage and dense irregular fibrous connective tissue. These tissues serve as a soft, growing structure and container for the boney skeleton that will replace them. As development and growth continue, blood vessels start to grow and expand into the soft fetal skeleton, in taking stem cells and nutrients for bone growth Osseous tissue gradually substitutes the cartilage and fibrous tissue in a process described as calcification. The calcified regions expand out from their blood vessels replacing the old tissues until they touch the border of another bony region. At childbirth, the skeleton of a newborn has more than 300 bones, as a person ages, These bones grow together and merge into larger bones. Thus adults are left with only 206 bones.
Flat bones develop in the process of intramembranous ossification in which the young bones grow to form a primary ossification center in the fibrous membrane and leave a small area of fibrous tissue in connecting each other. In the skull, these soft spots are known as fontanels and from the skulls flexibility and room for the bones to expand. Bone gradually replaces the fontanels until the individual bones of the skull connect to form a hard adult skull.
Long bones develop under the process called of endochondral ossification in which the diaphysis develops within of cartilage from the main ossification center until it creates mot of the bone. The epiphyses then explain for secondary ossification centers on the ends of the bone. A small band of hyaline cartilage continues to be in between the bones on a growth plate. As we grow throughout childhood, the growth plates grow under the influence of growth and sex hormones, slowly separating the bones. At the same time, the bones examined by growing back into the growth plates. This process continues until the end of puberty when the growth plates stop increasing, and the bones fuse permanently into a single bone, The immense different in height and limb length among birth and adulthood are mainly the results of endochondral ossification in the long bones.