Unit 7 Reflection

In this unit, we learned about the major muscles in the body, and in a chicken; how various muscles work in order to create a certain desired movement, the contraction and relaxation of muscles, and the affects of different types of performance enhancing drugs. In the beginning of this unit, we started out learning about the directional capabilities of the synovial joints ranging from abduction and adduction- the movement of limbs away and toward the body- to inversion and eversion- which turns the sole of the foot inward and outward.

Moving onto the muscular system, we learned about the properties of muscle tissue- which include contractability, the ability of the muscle to shorten when stimulated; extensibility, the ability to be stretched; and elasticity, which is the ability of the muscle to recoil to resting length. In classifying the muscles, there is the "prime mover" which causes a desired action, the antagonist which relaxes when the prime mover contracts, the synergist which assists the prime mover by reducing unnecessary movements, and the fixator which stabilizes the origin of the prime mover.

Then, we learned about how the muscle contracts and retracts. During contraction, the nerve sends an impulse to the muscle, and Ca+ ions are released into the sacroplasmic reticulum, the Ca+ binds to proteins around actin filaments, the binding of the Ca2+ causes myosin filaments to pull on the actin filaments, and the sarcomere is shortened. In relaxation, the impulse passes, the Ca2+ gate closes, and the Ca2+ is transported back to the sarcoplasmic reticulum. In order to demonstrate this process and how muscles work, we created a short video describing this.

Learning about the major muscles of the body made it easier to recognize the similar muscles during the dissection. In the chicken dissection , we were able to discover the pectoralis major, the pectoralis minor, that allows the chicken to close and open its wings; the gluteus maximus, and the hamstring group. When comparing the major muscles of the chicken to the major muscles of the human, many of the muscles were similar and helped complete the same desired actions.

Next, we learned about the three different muscle fiber types: slow twitch, fast twitch A, and fast twitch B. With slow twitch muscle fibers, they are best suited for long duration due to their slow contractability and high amounts of myoglobin. Both fast twitch A and B are better suited for shorter duration, as they have fast contractability and high glycogen storage. In order to keep the muscles strong and healthy, exercising and eating healthy are required. Fast twitch muscles are improved by brief and intense workouts, and slow twitch fibers can be improved by cardiovascular training.

Lastly, we learned about the causes and effects of using performance enhancing drugs. Many individuals begin the use of performance enhancing drugs due to the pressures from peers, role models, media influences, and self body image. Specific effects of using performance enhancing drugs are severe and negative as it can cause high blood pressure, liver damage or cancer, or blood clots and stroke.


If there are so many detrimental effects to the use of performance enhancing drugs, why do individuals still continue to take the risks? Throughout this school year, I feel as though I have grown into a better student and have become more concentrated on living a healthier lifestyle. With my New Year's goals, I am slowly making progress and focusing more on managing my stress and sleep levels as I realized the effects it was having on my body- making me constantly tired throughout the day.