6. Distal epiphysis Proximal epiphysis diaphysis yellow marrow epiphyseal line periosteum compact bone spongy bone Endosteum hyaline cartilage Anatomy of a Long Bone Sharpey’s fibers
41. cartilage calcified cartilage bone epiphyseal plate epiphyseal line Endochondral Ossification 2 o ossification center Fetus: 1 st 2 months Adult Childhood Just before birth
48. Rickets - vitamin D deficiency Osteomalacia - soft bones, inadequate mineralization in bones, lack of vitamin D Pagets Disease - spotty weakening in the bones, excessive and abnormal bone remodeling Rheumatoid arthritis - autoimmune reaction Diseases of the Skeletal System:
49.
50.
Editor's Notes
Osteoblasts Osteoblasts are responsible for building new bone and lie at the centre of bone physiology. Their functions include the synthesis of collagen and the control of mineralisation. Osteoclasts Osteoclasts are specialised cells that resorb bone. They work by sealing off an area of bone surface then, when activated, they pump out hydrogen ions to produce a very acid environment, which dissolves the hydroxyapatite. Osteocytes Bone adapts to applied forces by growing stronger in order to withstand them; it is known that exercise can help to improve bone strength. Osteocytes are thought to be part of the cellular feed-back mechanism which directs bone to form in the places where it is most needed. They lie within mineralised bone and it is thought that they may detect mechanical deformation and mediate the response of the osteoblasts.