Muscle Contraction Research Paper

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Research Paper! 1 Contraction and Relaxation of Skeletal Muscle Fiber It would be impossible to do anything without your muscles so, have you ever stopped to wonder how your skeletal muscles actually move to contract and then relax after a contraction? In this essay, the key steps involved in contraction and relaxation of skeletal muscle fibers and how rigor mortis relates to muscle contraction/relaxation will be explained. Muscle contraction starts when a neuron action potential arrives at the the end of motor neurons. Then a neurotransmitter, called acetylocholine (ACh), is released and the ACh binds to receptors on motor end plates and sodium ions then move into muscle fibers. The next step is the muscle action potentials move into the Ttubules where calcium is released by the sarcoplasmic reticulum and the calcium binds to a binding…show more content…
As the calcium gets pumped back into the sarcoplasmic reticulum, calcium ions come off the troponin. The troponin returns to its normal shape and allows tropomyosin to cover the actin-myosin binding sites on the actin filament. Because no binding sites are available now, no crossbridges can form, and the muscle relaxes neurotransmitter, ACh is broken down in the neuromuscular junction and there is no longer action potentials that travel down the T-tubules and the calcium returns to the terminal cisternaes. Rigor Mortis relates to muscle contraction and relaxation because it is know as the stiffness of death. There is a biochemical change in the muscles that occurs several hours after death. The hydrolysis in the muscle of ATP is the biochemical bases of rigor mortis and without ATP, myosin molecules adhere to the actin filaments and the muscles become rigid. So, because no ATP is available the skeletal muscles lock into a contracted position and the body of the deceased individual becomes rigid. This is called Rigor
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