David Shenk recognizes that “our muscles and brain regions
adapt to the demands that we make of them.” He backs up his claim by quoting
Swedish psychologist Anders Ericsson who says deliberate practice “is shown to
induce physiological strain which causes biochemical changes that stimulate
growth and transformation of cells” (67). What are some of these biochemical
changes and in what ways can a cell be transformed?
Lizzy Ettleson, lettleson@gmail.com
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ReplyDeleteSince our “muscles and brain regions adapt to the demands that we make of them”, our body starts to learn the specific behavior. Many professional sports players practice many hours a day every day because by using the same muscles and doing the same actions, the body has developed a response/learned to the stimulus (Campbell 1125). To give an example, let’s look at a baseball player. A baseball player’s bicep and tricep muscle fiber cells contain more myofibrils than a normal human being. When a baseball player sees a ball coming towards him, his brain sends an electrical impulse down to the muscles via nerve cells to myofibrils, which are receptor protein which binds to the membrane of a muscle cell, allowing it to contract. By constant practice, the brain will learn to send electrical impulses to myofibrils every time it sees the stimulus of a ball being pitched, which increases efficiency by increasing response time. By using their biceps and triceps to bat, the body has to make more myofibrils, and the muscle cells in the biceps and calves have also adapted to receive more oxygen from the blood by widening the membrane of the myocyte. Additionally, a baseball player’s body will also have highly developed bicep and tricep muscle due to constant use of muscle fibers which will tire them out, so the body sends enzymes to break up the muscle fiber cells by duplicating or splitting them, which leads to greater muscle mass. When humans perform aerobic exercises every day, it causes metabolic-related changes in human skeletal muscle such as upregulating of extracellular matrix and calcium binding gene families after training. Differential gene expression can change gene expression by acetylating lysines in histone tails which allows for less binding of the histone tail to the neighboring nucleosomes, which allows for easier transcription. The binding of activators and repressors to the control elements of the enhancers will also change rate of gene expression, which could lead to the production of more or less muscle binding proteins. Lastly, a gene’s expression may be changed by post-transcriptional methods such as alternative RNA splicing, which creates different mRNA molecules based on RNA processing in the nucleus. This allows a cell to fine-tune gene expression such as making more myofibrils or widening of a myocyte membrane.
ReplyDeletehttp://www.ncbi.nlm.nih.gov/pubmed/15857889
Yiran Xu, yxu135@gmail.com