The Muscular System
This web page is to assist AP Bio students in learning the muscular system through videos, discussion, guided questions, diagrams, and even links to other websites that can help you. We hope you use this page if you ever need help.
Enjoy!
An In-Depth Look At The Muscular SystemThe muscular system is one of the most vital components of the human body in that many essential organs of the human body are types of muscles that allow for different
functions. First, let's talk about muscle cells. Human muscle cells store calcium ions; a sarcoplasm, which is the cytoplasm of muscle cells; and the sarcoplasmic reticulum, like the endoplasmic reticulum, a network of tubes. In the sarcoplasm, muscle cells have several more mitochondria for the production of Adenosine Triphosphate (ATP) by cellular respiration. ATP is the chemical energy that allows humans and all other organisms to carry out necessary functions. Because muscle cells are involved in rigourous activities like exercise and any form of motion, much more ATP is needed to be produced than any other type of body cell. As a result, much more mitochondria are needed in these cells. Now let's discuss the types of muscle. There are three types: smooth muscle, cardiac muscle, and skeletal muscle. Smooth muscle, like the stomach, is involuntary. This means that you do not have to physically move it yourself like you would your arms and legs in order to make it work. The same applies to cardiac muscle, your heart. If you were forced to remember to move your heart on your own without your body doing it itself, you would die an excruciatingly painful death. Skeletal muscle refers to those in your arms, legs, neck, etc. These require a voluntary movement to make them work. These muscles are involved in the actual action of running and exercise. Although the AP exam does not focus on the muscular system in depth, they like to play tricks on you so knowing some of these facts may help you on the exam, like how muscles are structured and how they work. To answer those questions, we will focus on the skeletal muscles, because they are the easiest to talk about! What you need to know is that ALL muscles work by contraction, the constricting and loosening of muscle fibers. Also, muscles always pull, not push. In regards to skeletal muscles, contracting allows for the movement of arms and legs, whether you are flexing or extending them. Skeletal muscles are made of muscle fibers (cells) that are divided into functional units called sarcomeres. Sarcomeres are alternating bands of thin and thick protein filaments (thin thick thin thick...). The thin protein filament is actin, which is a complex of actual braided actin molecules and fibers of a protein called tropomyosin and those fibers are composed of something called troponin. The thick protein filament is myosin, a long single protein with a globe-like head. These protein filaments interact through cross bridges, which connect the myosin heads to the actin. These cross bridges allow the actin and myosin to slide against one another to make contractions. A LOT OF ATP IS NEEDED FOR THIS! Finally, let me present a real life scenario for muscles. A sprinter's rapid pace causes the increased rate of contraction of the actin and myosin filaments. This increases the intake of oxygen gas and the increased rate of respiration. This makes a highly elevated amount of ATP and therefore much more energy for the sprinter to finish the race. |
Be able to answer these questions after watching the video!What are the three types of muscle?
Where are they located? What attaches muscles to bones? What is a sarcomere? What are the two microfilaments associated with muscle contractions? What is necessary for the actin/myosin system to work? For More Information Check Out This Website and Follow Along With These Guided Questionshttp://training.seer.cancer.gov/anatomy/muscular/structure.html
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