The neuromuscular system (P1) Flashcards
What are the three main types of muscle fibre?
. Slow oxidative/slow twitch (type I)
. Fast oxidative glycolytic (type IIa)
. Fast glycolytic (type IIb)
Explain slow twitch fibres (type I)?
Slow contraction speed which means it is better adapted to lower intensity exercise such as long distance running.
Explain fast twitch fibres (typeII) generally?
Fast contraction speed and provide a strong force of contraction. They also fatigue quickly and are only used for short, intense bursts of effort. Most of the energy is provided anaerobically.
Explain fast oxidative glycolytic fibres (type IIa)
less resistant to fatigue (than type IIb) so are used for events such as 1500m where a longer burst of energy is needed.
Explain fast glycolytic fibres (type IIb)
Fatigue much quicker and used for highly explosive events such as 100m.
What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type I fibres?
slow(110), small, slow, low, low, high, high, high, very high, low, low
What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type IIa fibres?
fast (50), large, fast, high, medium, medium, medium, medium, medium, high, high
What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type IIb fibres?
fast (50), large, fast, high, high, low, low, low ,low, very high, very high
How can muscle fibre size be increased through training?
Muscular hypertrophy.
What is a motor unit?
A motor neurone and its muscle fibres
What is a motor neurone?
Nerve cells which transmit the brain’s instructions as electrical impulses to the muscles.
What is the neuromuscular junction?
Where the motor neurone and muscle fibre meet.
What is the all or none law?
Where a sequence of impulses has to be of sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. If not, none of them contract.
What ways can be used to increase the strength of contraction?
wave and spatial summation
What is wave summation?
When there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction occurs , rather than twitches. Produces a tetanic contraction.
What is spatial summation?
When the strength of a contraction changes by altering the number and size of the muscle’s motor units.
What is PNF?
Proprioceptive neuromuscular facilitation is an advanced stretching technique
What are muscle spindles and golgi tendon organs?
Types of proprioceptors
What are muscle spindles?
These detect how far and how fast a muscle is being stretched and produce the stretch reflex. Found between skeletal muscle and tendons.
What are golgi tendon organs?
These are activated when there is tension in the muscle. Found between muscle fibre and tendons.
Briefly explain the first part of the CRAC technique of PNF?
Muscle is stretched until tension is felt. A stretch reflex will occur if it is being stretched too far.
Briefly explain the second part of the CRAC technique of PNF?
Individual isometrically contracts for a least ten minutes by pushing a muscle against a resistance. the golgi tendon organs detect the tension in the muscle and are activated and their inhibitory signals override the excitory signals by the muscle spindles. delaying the stretch reflex.
Briefly explain the third part of the CRAC technique of PNF?
The leg is lifted again like part 1 but can be pushed further because the golgi tendon organs have caused the antagonist to relax so the leg can stretch further.
