{"type":"video","version":"1.0","html":"<iframe src=\"https://www.loom.com/embed/a0657d3b56ab4a3fb0b3cf356701aca3\" frameborder=\"0\" width=\"1662\" height=\"1246\" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>","height":1246,"width":1662,"provider_name":"Loom","provider_url":"https://www.loom.com","thumbnail_height":1246,"thumbnail_width":1662,"thumbnail_url":"https://cdn.loom.com/sessions/thumbnails/a0657d3b56ab4a3fb0b3cf356701aca3-85ef783193d232a4.gif","duration":2111.183,"title":"Muscle Physiology, Excitation Contraction Coupling","description":"This Loom explains muscle physiology, following the pathway of a voluntary contraction and how muscles excite, contract, relax, and produce force. It covers the neuromuscular junction with acetylcholine release, T-tubules and calcium release from the sarcoplasmic reticulum, excitation-contraction coupling via troponin and tropomyosin, and the cross-bridge power stroke using ADP, inorganic phosphate, and ATP, ending in sarcomere shortening through sliding filament mechanisms. It also describes relaxation by removing acetylcholine with acetylcholinesterase and pumping calcium back into the sarcoplasmic reticulum, and notes rigor mortis occurs after 24 to 48 hours without ATP. The discussion then adds motor unit recruitment and the size principle, plus twitch types, fiber types, energy systems, and brief clinical notes including myasthenia gravis, organophosphate poisoning, botulinum toxin, and DOMS."}