Osteoporosis And Effects Of Gavity And Space

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the bone marrow within its mid cavity and to top it all it is capable of changing its architecture and mass in response to outside and inner stress. It is this dynamic remodeling of bone which is of primary interest in microgravity. To feel the impact of this dynamicity it should be noted that a bone remodeling unit [a coupled phenomena of bone reabsorption and bone formation] is initiated and another finished about every ten seconds in a healthy adult. This dynamic system responds to mechanical stress or lack of it by increasing the bone mass/density or decreasing it as per the demand on the system. -eg; a person dealing with increased mechanical stress will respond with increased mass / density of the bone and a person who leads a sedentary life will have decreased mass/density of bone but the right amount to support his structure against the mechanical stresses she/she exists in. Hormones also play a major role as seen in postmenopausal females osteoporosis (lack of estrogens) in ...

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osteoporosis. Boy Frame,M.D a member of NASA�s LifeScience Advisory Committee [LSAC] postulated that "the initial pathologic event after the astronauts enter zero gravity occurs in the bone itself, and that changes in mineral homeostasis and the calcitropic hormones are secondary to this. It appears that zero gravity in some ways stimulate bone re-absorption, possibly through altered bioelectrical fields or altered distribution of tension and pressure on bone cells themselves. It is possible that gravitational and muscular strains on the skeletal system cause friction between bone crystals which creates bioelectrical fields. This bioelectrical effect in some way may stimulate bone ...

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