Muscle Fibers and Sarcomeres

by Jason Amores Sumpter
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muscle is made up of many muscle fibers. As you can see here in this diagram, these air long, thin my oocytes that actually contain multiple nuclei and they're going to be chock full of what are known as my oh federal my A fib. RL are these rod like protein structures that are going to be made of acting and my Yasin and these air What are going to do the contracting Now they're going to be arranged into units called Sarka Miers And these air essentially the Contract I'll units that will be chained together and formed longer. Myo Federal. So each SAARC Amir is gonna individually be contracting so that the longer Myo federal itself contracts now striated muscle like skeletal muscle in cardiac muscle gets its name. Because of these repeated units, notice sarka meters that give it a sort of lined pattern. Hence striations. Now SARC Amir's are going to be made of what are called thick and thin myo filaments and these air going to interact by sliding past each other to cause contraction. Now my Ofili mints take two forms. There are thin filaments which are made of acting and thick filaments that are made of Maya Seuin They're going Thio be joined together these Sark Amir's at what are known as Z discs. So here you can see our Sark Amir Hopefully you can seethe lined pattern in there The striations, if you will. And these dark lines are the Z lines. So what's between these Z lines or Z discs? Uh, either name really works. What's between These is one Sark Amir, and it's going to be made up of thes thick filaments that you see in blue here and thes thin filaments that you see in red and those air What? They're going to slide past each other to cause contraction like you see happening behind me here the thin and thick filaments are a little more spread out right. There's a little more distance here and here they are contracted. That's gotten a little bit smaller because essentially, what's happened is this Ah, they've moved past each other in this direction and we're actually gonna flip the page right now and take a look at how that happens.