Movement
Due to the ligaments that hold bones together, the bones work as levers driven by muscles. Moreover, the shape of the skeletal system facilitates movement; for example, the small bones of the hands warrant precise action, and the small bones of feet help people adapt to any terrain.
Protection
The skeletal system protects organs from damage, forming bone receptacles for the brain, spinal cord, and other vital organs. Being solid, the bones can withstand blows and pressure that other organs cannot oppose (Huang, 2017). A combination of three components determines the strength properties of bone tissue: collagen is responsible for strength, proteoglycans for elasticity, and hydroxyapatite crystals for stiffness.
Blood Cell Production and Storage
Due to the structure of spongy tissue within long bones, bones are responsible for blood cell production. Moreover, bones can store fat, which may turn into red bone marrow, becoming the source of new blood cells in case of severe red cells depletion.
Storage of Minerals/Mineral Homeostasis
Bones store minerals due to a specific structure of their tissue. There is an organic protein matrix within bones, which mainly consists of collagen—the fibers of collagen twist around each other, forming an internal basis for the deposition of minerals. When there is a shortage of minerals, the bone can releases the minerals into the blood.
Relationship between Vitamin D Deficiency and Fragile Bones
Vitamin D deficiency leads to a decrease in the intake of calcium through the intestines. In response, the production of parathyroid hormone increases, which maintains the average calcium level in the blood. In bones, the parathyroid hormone increases osteoclast cells’ activity that dissolves bone tissue, which leads to a decrease in bone mineral density with the development of the fragility of bones.
Reference
Huang, D. Y. (2017). The cloud classroom of the skeletal system. New Trends and Issues Proceedings on Humanities and Social Sciences, 4(1), 285-290.