Unit 8 Reflection

In this unit, we learned about the muscular system and the everyday role they play in our lives that allow us to function as human beings. One of themes of the unit were what are the major muscles of the body and what purpose do they serve. Instead of learning this through notes however, I instead learned it through our chicken lab dissection. The main muscles in the chest are the pectoralis major and minor, which aid humans in bench press and supports the arms. The trapezius muscle in the back helps support posture while the latissimus dorsi helps move the arms in multiple, fluid directions. The deltoids help raise and support the upper arms while the biceps brachii bends and flexes the arm. The triceps humeralis supports the lower arm and helps position the arm into normal position. The flexor carpi ulnaris provides movement to the hand and wrist while the brachiordialis flexes the forearm through the elbow and pronates and supinates the arm. The sartorius is an important flexor and rotator of the hip joint while the iliotibialis extends, abducts, and laterally rotates the hip. The biceps femurs helps flex the knee. The semimembranosus enables the leg to flex and rotate while the semitendinosus helps medially rotate the femur and tibia when the knee is extended. The quadriceps femoris flexes the thegh and helps with leg extensions while the gastrocnemius helps extend the foot and aids us on standing on our toes. Lastly, the peroneous longus extends the foot while the tibialis anterior flexes the foot and causes “shin splints”. Movement of the limbs through synovial joints were also incorporated into the unit. Skeletal muscles work in opposing pairs, known as flexors and extensors, to produce multiple types of movement. Muscles are organized through their name with factors such as direction, size, action, and number of origins, and location. Muscles are also classified through four terms: Prime Mover, Antagonist, Synergist, and Fixators. Prime movers cause a desired action such as elbow flexion while antagonist relaxes when prime mover contracts. Synergist muscles help the prime mover by reducing unnecessary movements while fixators stabilize the origin of the prime mover and can immobilize the bone. Muscles work based on whether they can contract or not. For a muscle to contract, nerve sends impulse to the muscle fiber, where Ca2+ ions are released from the sarcoplasmic reticulum into the cytoplasm. From there, Ca2+ binds to proteins wrapped around actin filaments. The binding of Ca2+ causes myosin filaments to bind to and pull on actin filaments. The sarcomere then shortens and the muscle begins to relax. As an impulse passes, Ca2+ gates close. As Ca2+ is transported back into the sarcoplasmic reticulum, the muscle relaxes. Another theme we learned was the facilitation of muscle fibers and how they respond to different types of exercise. These contractions play an important part when we stretch. There are three types of muscle fibers: Slow twitch, Fast twitch(a), and Fast twitch(b). Slow twitch fibers contract relatively slowly and are highly aerobic. FT(a) fibers are fast in contractile speed, moderately high oxidative capacity, and relatively fatigue resistant. FT(b) fibers are anaerobic, fatigue quickly, and have high glycogen stores. Slow twitch fibers and FT(a) fibers are usually involved in repetitive and long distance exercises while FT(b) fibers are involved in short exercises such as sprints and max repetition.    

I would have liked to learn about performance enhancing drugs such as HGH or other steroids and their negative impacts to the human body. I would have also liked to learn a little more about protein shakes and if they really do work or are just a waste of money and resources. Before the unit started, I only knew basic muscles that we use to lift weights. After this unit and the chicken dissection, I am glad to say I know more complex and intricate muscles and how they actually work instead of just basic muscles. 

My New Years Goals have been in a constant roller coaster this year. While my weightlifting habits have been fine and I have been achieving the goals I desired ( I currently passed 215 pounds), my grades have received a sudden shift. My goal for this year was to achieve an A in this class, but due to a zero on a lab that goal seemed impossible. However, with the new extra credit opportunity with cleaning up the creek, an A now seems reachable. If I can perform well on my cat dissection and my 20 time project, and volunteer at the creek, I can receive that A. Not only will this achieve my goal, but it will also cut my college tuition in half, which I am desperate for as I will be paying for college by myself without my parents. Either way, at the end of the day, I need an A in this class, and I believe in myself that I WILL get an A in this class.