ES 2030 Lecture Notes - Lecture 5: Weight-Bearing, Manganese, Menopause
Document Summary
Chemical composition of bone: 1/3 is organic and contains: Osteoclasts: large cells that reabsorb or break down bone matrix: 2/3 of bone is inorganic and contains: Collagen fibers: combination of organic/inorganic provides strength and resilience. Bone adapts to tension and compression by varying proportions of minerals and collagen fibers. Response to mechanical stress: large, bony projections occur where heavy, active muscles attach, wolff"s law: the more force you put on a bone, the stronger (denser) it will become. Bone development: ossification: process of bone tissue formation which leads to . Formation of bones begins at week 8 in womb. Hormones: during infancy/childhood, bone growth is stimulated by growth hormone, during puberty, testosterone/estrogen promote growth spurts , rising blood ca2+ levels trigger the thyroid to release calcitonin (stimulates calcium deposit in bone) Importance of ionic calcium in body: transmission of nerve impulses, muscle contraction, blood clotting, secretion by glands and nerve cells, cell division.
