1.3: The Neuromuscular System Flashcards
What is the autonomic nervous system?
- regulates the function or our internal organs such as the heart and also controls some of our skeletal muscles within the body.
What is the neuromuscular system?
- where the nervous system and the muscles work together to allow movement.
Changes in the neuromuscular system:
- take place before, during and after exercise.
- these changed prepare the body for exerciser and allow for the change into demands of different intensities or exercise.
Sympathetic nervous system - during exercise:
- part of the peripheral nervous system
- prepares the body for exercise and is often referred to as the ‘fight or flight response’
Parasympathetic nervous system - during exercise:
- has the opposite effect of the sympathetic nervous system
- relaxes the body and slows down many high energy functions.
‘rest and relax’
What are the three types of muscle fibre?
- slow oxidative (type 1) (also known as slow twitch)
- fast oxidative glycolytic (type 11a)
- fast glycolytic (type 11x)
The relative proportion of each fibre type in different people?
- varies, e.g, in an elite endurance athlete there will be a greater proportion of slow twitch fibres in the leg muscles, and in the elite springer a greater proportion of fast twitch fibres in the leg muscles.
- postural muscles tend to have a greater proportion of slow twitch fibres as they’re involved in maintaining body position over a long period of time.
What are slow twitch fibres?
- slower contraction speed than fast twitch fibres
- better adapted to lower intensity exercise such as long-distance running.
- they produce most of their energy aerobically - therefore have certain characteristics that allow them to use oxygen more effectively.
- red in colour due to high volume of myoglobin. This therefore results in high levels of mitochondria and oxygen.
- very resistant to fatigue - LD running, e.g. marathon runners.
What are fast twitch fibres?
- must faster contraction speed and can generate a greater force of contraction.
- however they fatigue very quickly and are used for short, intense bursts of effort.
- they produce most of their energy anaerobically.
- two types
What are the two types of fast twitch fibres?
- type 11a (fast oxidative glycolytic; these fibres are more resistant to fatigue and used in events such as the 150 in athletics where a longer burst of energy is needed.
- type 11x (fast glycolytic; these fibres fatigue much quicker than type 11a and are used for highly explosive events such as the 100m in athletics where a quick, short burst of energy is needed.
Characteristics of slow and fast twitch fibres - type 1:
- contraction speed (metres per second): slow (110)
- motor neurone size: small
- motor neurone conduction capacity: slow
- force produced: low
- fatiguability: low
- mitochondrial density: high
- myoglobin content: high
- capillary density: high
- aerobic capacity: very high
- anaerobic capacity: low
- myosin ATPase/glycolytic enzyme activity: low
Characteristics of slow and fast twitch fibres - type 11a:
- contraction speed (metres per second): fast (50)
- motor neurone size: large
- motor neurone conduction capacity: fast
- force produced: high
- fatiguability: medium
- mitochondrial density: medium
- myoglobin content: medium
- capillary density: medium
- aerobic capacity: medium
- anaerobic capacity: high
- myosin ATPase/glycolytic enzyme activity: high
Characteristics of slow and fast twitch fibres - type 11x:
- contraction speed (metres per second): fast (50)
- motor neurone size: large
- motor neurone conduction capacity: fast
- force produced: high
- fatiguability: high
- mitochondrial density: low
- myoglobin content: low
- capillary density: low
- aerobic capacity: low
- anaerobic capacity: very high
- myosin ATPase/glycolytic enzyme activity: very high
Hypertrophy definition:
- where the muscle has become bigger and stronger
- it is possible to increase the size of muscles fibres through training.
What is a motor unit?
- consists of a motor neurone and it’s muscle fibres.
- only one type of muscle fibre can be found in one particular motor unit.