Structure and function of the muscular system
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Structure & Function of the Muscular System Task One The human body contains more than 650 individual muscles which are attached to the skeleton. This provides the pulling power for us to move around. The main job of the muscular system is to provide movement for the body. The muscular system is split into 3 categories of muscle tissue - skeletal, smooth and cardiac. Each different tissue has the ability to contract, this allows the body's movements and functions. There are two types of muscles involuntary which contract and relax automatically inside your body. These cannot be controlled. Then there is voluntary muscles which are muscles that can move whenever you want. Heart or cardiac muscle is an example of an involuntary muscle. Cardiac Muscle The cardiac muscle is the muscle of the heart. It is the tissue that makes up the wall of the heart called the myocardium. Like the skeletal muscles, the cardiac muscle is striated and contracts through the sliding filament method. But the cardiac muscle is different from other types of muscles because it forms branching fibres. Unlike the skeletal muscles, the cardiac muscle is attached together instead of bone. The cardiac muscle is fatigue resistant because it doesn't get tired, if it did then we wouldn't be alive. The strength of contraction is high because our heart has to pump blood around the body.
* Type 2a - Fast Oxidative Glycolytic (FOG) * Type 2b - Fast Glucolytic (FG)# Fast and Slow twitches Fast twitch fibers demonstrate a high capability for electrochemical transmission of action potentials and a very fast level of calcium release and uptake by the sarcoplasmic recticulm. Fast twitch fibers rely on well developed, short term, glycolytic system for energy transfer and contract and develop tension at 2-3 times the rate of a slow twitch fiber. Slow twitch fibers generate energy for ATP re-synthesis by means of a long term system of aerobic energy transfer. They usually have low activity level of ATP. They contain large and numerous mitochondria and have high levels of myoglobin that gives them a red pigmentation. They have been demonstrated to have high concentration of mitochondrial enzymes, this means they are fatigue resistant. In terms of people who participate in athletics: Type 1are red fibers and is often called slow oxidative also called slow twitch or fatigue resistant fibers. They contain large amounts of myoglobin and the type 1 generates ATP (Adenosine Triphosphate) by the aerobic system (oxidative). It is split ATP at a slow rate and has slow contraction velocity (thin myeline system). Type one has many mitochondria (where aerobic energy is produced in cells) and many blood capillaries (lots of 02). Type 1 is also resistant to fatigue, found in large numbers in postural muscles.
An example is an arm stroke when swimming, the even resistance from the water offers a constant speed. Muscles produce movement by electronic signals being sent through the neurones of the brain to the place where movement is desired. When the signals reach this spot they close an electric pathway and tells the muscle to expand or contract. BTEC Sport & Exercise Science Textbook - Jennifer Stafford-Brown, Simon Rea & John Chance Task Five When muscles contract they work as a group in that the muscle contracting in dependant on other muscles to enable it to do its job. A muscle can play one of four roles: Antagonistic Muscle Pairs- As one muscle contracts the other relaxes. Antagonist- This muscle relaxes to allow the agonist to contract. Agonist- (prime mover) this muscle contracts to produce the desired movement. Synergist- this muscle assists the agonists in producing the desired movement to occur. Fixator- these muscles fix joints and the body in position to enable the desired movement to occur. Bicep Curl When performing a bicep curl the antagonistic pair in the muscle which contracts to produce the movement and the muscle relaxes to allow the movement to occur. During this the synergist will assist the agonist (bicep brachii) to produce the desired behaviour. The tricep brachii on the other hand will be the antagonist because it relaxes to allow the movement to occur. Then the fixator helps the muscle fix joints and the body in position to enable the desired movement to occur.
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