a) Describe age-associated changes in human bone and their consequences in terms of physiological function  b) Discuss how keeping physically active may help to maintain physiological function in human bone during the ageing process

Discuss the stress-strain relationship on bone. In your discussion, include a graph of the stress-strain curve.

Osteoporosis is a condition in which the activation of certain signal transduction pathways causes calcium to be removed from bones, leaving them brittle and more likely to break under moderate pressure. Current research suggests that osteoporosis can be initiated under conditions of low cal- cium intake in order to increase the availability of calcium for other biological roles in the body. Which of the following describes the conditions that would be most likely to initiate osteoporosis? A B с D insufficient amounts of calcium to allow the replication of DNA molecules during cell division insufficient amounts of calcium to maintain the membrane potential established by the sodium-potassium pump insufficient amounts of calcium ions to facilitate efficient transduction of neuronal signals insufficient amounts of calcium to be used in the fixation stage of the Krebs cycle in photosynthesis

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