[Age related differences in muscle plasticity]

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ACKNOWLEDGEMENT

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.



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I [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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ABSTRACT

In this study we try to explore the concept of “Age related differences in muscle plasticity” in a holistic context. Muscle plasticity is a process in which muscle adapts, with consequent modifications to structural and/or functional phenotypes, in response to a stimulus. Stimuli include contractile activity, loading conditions, substrate supply, and environmental factors. These adaptive events occur in both muscle fibers and associated structures (motoneurons and capillaries), and they involve alterations in regulatory mechanisms, contractile properties and metabolic capacities. Muscle is remarkably adaptable to its functional load. The noticeable characteristics of aging include the muscular mass and its strength loss. Changes associated to neuromuscular system can help in understanding the reason of the loss. These changes may include reduced muscle fiber, reduced in quantity of muscle fiber and reduced number of neurons of motor. It is of high importance to find out the reason for muscle plasticity. It is possible that muscle plasticity may be result of sedentary lifestyle or it may be due to the natural aging process. In this research we have assumed that muscle plasticity is affected by the age and after the research we have come to the conclusion that is it affected by the age. An increase in activation time (endurance exercise) or an increase of the load (resistance exercise) results in a change in muscle phenotype by inducing the expression of genes involved in processes such as muscle hypertrophy, the transition of muscle fibre types and mitochondrial biogenesis. Plasticity is adaptability to change or flexibility, in response to functional demands, with consequent modifications to structural and/or functional phenotypes. In biology, phenotypic plasticity is an ability of a genotype to express different phenotypes, adaptive or environmentally constrained by experience. The plasticity of skeletal muscle implies the existence of mechanisms to detect changes in contractile activity and environmental factors. The current state of research explains, however, far not all the possible interactions between the elements affecting muscle function and adaptive process of skeletal muscle classically described. Skeletal muscle is a complex, versatile tissue composed of a large variety of functionally diverse fibre types. The overall properties of a muscle largely result from a combination of the individual properties of its different fibre types and their proportions. Regarding adaptations to change function, gene expression and structural phenotype in relation to demand or environmental pressure, satellite cells are the `agent' of rapid, prolonged and persistent change during muscle development, growth, responses to disease or injury, and regeneration. In adult skeletal muscle, the self-renewing capacity of ...