Description of Action Potential in Skeletal Muscle Contractions, Summaries of Anatomy

Download Description of Action Potential in Skeletal Muscle Contractions and more Summaries Anatomy in PDF only on Docsity! Jenin Masalmah Br. Mustafa Babaa Anatomy and Physiology 10 February 2023 Action Potential in Muscles Before a muscle contraction is produced, many chemical processes occur first. To begin, the muscle is given a signal by the nervous system. The meeting area of the skeletal muscles and the neuron is called the neuromuscular junction. The space between them is the synaptic cleft. Within the neuron are neurotransmitters known as “acetylcholine”. The end of the neuron, axial terminal, activates acetylcholine when the brain gives a muscle impulse. When the acetylcholine is released into the synaptic cleft, acetylcholine receptors take in the released chemicals and open the muscle membrane or the ion channel. Now that the membrane is opened, the exchange of sodium (Na) entering and potassium (K) leaving is made. Sodium will enter in greater numbers causing a potential difference along the membrane. Before the positive sodium is brought in, the cell is mainly negatively charged. With all the new positive charges depolarizing the cell, other parts of the membrane open up rushing in more sodium. The channel eventually must close, and stop sodium from entering. The enzyme, acetylcholinesterase, breaks down the acetylcholine to prevent it from opening the channel any further. The action potential continues the process and allows the sodium — already in the cell — to travel deeper into the cell via T tubules to reach other parts of the muscle as well as to release calcium for contractions. After some time, repolarization occurs to restore the balance of potassium in the cell. The cell is then reset into resting potential, ready for another contraction impulse.