The Body In Action Assignment. Muscles and the effects of exercise.

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Muscular System

The muscles we have in our body are divided into three classes of muscles:

Cardiac – Cardiac muscles are involuntary and found only in the heart. They are controlled by the lower section of the brain called the medulla oblungata, which controls involuntary action throughout your body.

Smooth – Your smooth muscles, like your cardiovascular muscles are involuntary. They make up your internal organs, such as your stomach, throat, small intestine and all others except your heart.

Skeletal – The skeletal muscles are the only voluntary muscles of your body, and make up what we call the muscular system. They are all muscles that move your bones and show external movement.

Fibre Type

Type 1 - These fibres, also called slow twitch or slow oxidative fibres, contain large amounts of myoglobin, many mitochondria and many blood capillaries. Type 1 fibres are red, they split adenosine triphosphate (ATP) at a slow rate, they have a slow contraction velocity, are very resistant to fatigue and have a high capacity to generate ATP by oxidative metabolic processes. These fibres are found in large numbers in the postural muscles of the neck. The sporting event that is best related to type 1 fibres is athletics and the event would be a long distance event.

Type 2A - These fibres, also called fast twitch or fast oxidative fibres, contain very large amounts of myoglobin, very many mitochondria and very many blood capillaries. Type 2A fibres are red, they have a very high capacity for generating adenosine triphosphate or ATP by oxidative metabolic processes, they split ATP at a very rapid rate, they have a fast contraction velocity and are resistant to fatigue. Such fibres are infrequently found in humans. The sporting event that is related to type 2A fibres is athletics and the event being 100M sprinting.

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Type 2B - These fibres, also called fast twitch or fast glycolytic fibres, contain a low content of myoglobin, relatively few mitochondria, relatively few blood capillaries and large amounts glycogen. Type 2B fibres are white, they are geared to generate adenosine triphosphate or  by anaerobic metabolic processes, they are not able to supply skeletal muscle fibres continuously with sufficient ATP, they tire easily, they split ATP at a fast rate and have a fast contraction velocity. These fibres are found in large numbers in the muscles of the arms. The sporting event that is related to type 2B fibres is ...

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