Unit 7 Relfection

This unit was all about movement: what moves, what causes the movement, and what types of movement there are. We first learned about the different types os movement that synovial joints can do and had to make a dance out of the, sounds easy but to just move your arm there are probably three different things you need to specify about it like: Is your hand supinated or pronated? Is your wrist flexed or extended?  How about your elbow? What type of movement is your whole arm doing? Adduction? Abduction? Circumduction? Is your shoulder elevated or depressed? There is a whole lot to think about when you move your body because so many things are happening simultaneously and there is a term for each and every one of them. As a dancer of sorts this was all very fascinating and also slightly painful because one thing you never do as a dancer is invert your feet... ew, just no.

Now we move onto the structures that cause all this movement, the muscles themselves. We did review smooth muscle and cardiac muscle and how it different from skeletal muscle, but we focused on the relationship between the skeletal muscle and the joints. Skeletal muscles are attached to the bones via tendons, and are held together by several layers of connective tissue to keep the fibers in a muscle shape. Muscles also come in pairs, the antagonist and the synergist, because when one muscle contracts, the other muscle needs to relax to allow movement. The muscles all work together to create the movement and this was shown very well during our chicken dissection when I discovered I could make the chicken wave hello by rotating the humorous. I would put the video on this post but apparently the file is too large this time so here is the post about the chicken dissection with the video on it (it's really funny, I recommend watching it).

Muscle seem to have confusing names at first because they are all complicated latin words but each of the words have a pretty strait forward meaning and once you know those, identifying muscles is pretty easy. The different categories of classification are shape, size, number of attachments, location, and/or action. Each muscle in your body has a specific purpose and is designed to do that job. The steps for each muscle cell to do its job are quite complicated because muscle contraction is very quick and many things have to happen instantaneously. Firstly, your brain has to send a neural impulse to the muscle to send the action potential and release the acetylcholine to the muscle cell. The Ach causes the second action potential in the sarcoplasmic reticulum, releasing calcium into the sarcoplasm and attaches to the TT complex to change its shape. This shape change allows the myosin bonding sites on the actin to be available. ATP then attaches to the binding site on the myosin crossbridge and turns to ADP and P which causes the myosin head to extend and grab onto the actin. The P leaves followed by the ADP moving the myosin head downward, pulling the actin, causing the sarcomere to contract. We made a stop motion video showing all of this and you can watch it here.
We also learned about steroids and how they affect the body. Steroids are commonly heard about but there are many more types than people think because a steroid is a performance enhancing drug and PED's range from Human Growth Hormones to caffeine. The performance enhancing substances have temporary positive affects, but worse side affects that aren't worth getting those "mirror muscles" as Mr. Orre always says. Human Growth Hormone, for example, may gain muscle mass, but it causes joint pain and weakness making those large muscles useless. This is just one example, but many of those types of drugs have similar side affects. We actually made a satirical advertisement for this which you can view here. I drink too much caffeine and knowing what it does to my body won't stop me from drinking it when needed but I will definitely make sure not to become completely dependent on it.
I really wish we had more time to talk about the muscle themselves because this unit has gone by so fast and seems like we just learned all the material without time for it to sink in so I couldn't fully appreciate the part of the unit that I personally like the most, the muscles and their movements. I would love to have several weeks focusing on just the major muscles, and maybe even some of the non-major ones, so we could fully understand what and where they are and what they do. The unit may have gone by very quickly because I haven't exactly been staying with my goal to get sleep so the lack of sleep makes school seen very fast and overwhelming but I find the muscles interesting so I managed to keep it together.