Sliding Filament Mechanism in Anatomy and Physiology, Summaries of Anatomy

Download Sliding Filament Mechanism in Anatomy and Physiology and more Summaries Anatomy in PDF only on Docsity! Jenin Masalmah Br. Mustafa Babaa Anatomy and Physiology 9 February 2023 Sliding Filament Mechanism As we know, the skeletal muscle has many layers and tools used to create a contraction. The sliding filament theory is mainly focused on the protein chains deep within the muscle sarcomere. The two protein chains that produce a contraction are actin and myosin. The process indirectly begins in the muscle fiber or the myocyte. A lower motor neuron communicates with the myocytes to depolarize the muscle membrane and deep within the fiber with positively charged sodium and to release stored calcium in the muscle for later use. Now to the sarcomere structure with myosin and actin; when the muscle is relaxed, the actin is locked by a protein called “tropomyosin” and “troponin”. To release this protein lock, troponin, we need calcium! Due to the earlier step of the calcium release from the myocyte, the calcium floating around attaches and opens the actin chain to be used with the myosin heads. To attach the myosin heads to the actin chain we need a nucleic acid called ATP or “adenosine triphosphate”. The ATP binds to the myosin head, dissociates and becomes “adenosine diphosphate” or ADP and a phosphate. This forces the myosin to move and lock into the actin chain pocket and shortens the sarcomere. To release the myosin head, the ADP and one phosphate leave, making the myosin head fall back into position to shorten the other parts of the actin chain. This process of ATP, ADP, and phosphate being added and lost are repeatedly continued until muscle contraction is finished.