92713
Descrição
FlashCards por alexlpeart, atualizado more than 1 year ago
|
Criado por alexlpeart
aproximadamente 11 anos atrás
|
|
| Questão | Responda |
| Describe changes in human muscle contractile character with increasing age. | They become slower, weaker, Less muscle fibers, Less motor units, Slower switch on and off (reduced activity of sarcoplasmic reticulum) |
| How much of our muscle mass do we lose by the time we are 70? | 30% |
| Explain the reason for reduced activation of muscles as we age? | we lose 50% of our motor units when elderly, and there are less alpha motor neurons found in the spine. |
| Describe the process of collateral innovation and why this might results in muscle fiber types being arranged in a mosaic pattern. | Fast motor units die first. Slow motor units take over the deinnervated fast fibers. Due to the chronic low level stimulation fast fibers are converted to slow twitch fibers, when they are not fully adapted we see a mix of fibers under the control of one motor unit. This causes large patches of muscle to be the same fiber type. |
| Does activity stop the process of aging? explain | No, it just slows the process of aging. |
| Describe how motor units are remodeled during aging. | fewer motor units, more fibers per motor unit, less fibers in total, less fast motor units, slow motor units increase in size but no change in number. |
| What happens to the fiber twitch when we change one fiber type. | total time course of twitch wont change, time to maximal contraction might change. |
| Describe what happens to the sarcoplasmic reticulum efficiency as we age. How can this affect our muscle endurance? | Decreased efficiency, meaning our muscles wont become fully relaxed thus reducing blood flow to the muscles and decreasing the time it takes for them to fatigue due to the build up of metabolites and fall of fuel. |
Quer criar seus próprios Flashcards gratuitos com GoConqr? Saiba mais.