KINESIOL 4SS3 Lecture Notes - Lecture 8: Bone Resorption, Bone Density, Hip Fracture
19 Sep 2016
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Document Summary
Reservoir for minerals, systematic regulatory hormones, and inflammation- mediated factors: immune system help. 99% of body ca2+ lies in bone: many functions in the body, metabolic processes. Bone is a dynamic tissue, undergoing continuous cycles of formation and resorption (remodelling), based on the activity of 2 cells: osteoblasts (formation, osteoclasts (resorption, bone remodelling cycle. Preosteoclasts start chipping away at bone (chewing up) Osteoclasts (bigger bone eating cells) dig greater cavity. Osteoblasts fill in portion of bone eaten away by osteoclasts. Cavity progressively fill up bone and add minerals. Typical cycle could be close to a year. Any study less than 6 mo would not include full cycle and not accurate. Study should be at least 9 mo to capture full remodelling cycle. Young bone formation >bone resorption: greater blasts than clasts, blasts adding more minerals. Young adulthood formation = resorption: clasts = blasts. After ~3rd decade resorption > formation: whatever clasts after questions, blasts don"t completely fill in, osteopenia, osteoporosis.
