Neuromuscular System Flashcards
What is the name of Type I muscle fibres?
Slow oxidative
What type of sports are used by Type I muscle fibres?
Aerobic
Low intensity
E.g long distance, endurance athletes
What are some features of type I muscle fibres?
High number of mitochondria
High myoglobin
High capillary density
Low fatigability
What is Type IIa muscle fibre called?
Fast oxidative glycolytic
What type of sports use type IIa muscle fibres?
Games players
Middle distance e.g 1500m
What are the characteristics of type IIa muscle fibres?
Medium mitochondria
Medium myoglobin
Medium aerobic capacity
High anaerobic capacity
Medium capillary density
What are type IIx muscle fibres called?
Fast glycolytic
What type of sports use type IIx muscle fibres?
Anaerobic
Sports that used force and speed
E.g sprinting, javelin, weightlifting
What are the characteristics of type IIx muscle fibres?
Low mitochondria
Low myoglobin
Low capillary density
High fatigability
Lots of phosphocreatine available to provide energy
What is a motor unit?
A motor neurone and its muscle fibres
What is a motor neurone?
Nerve which transmits the brain’s instructions as electrical impulses to the muscles
What is a neuromuscular junction?
Where the muscle fibre and motor neurone meet
How many types of muscle fibres are in each muscle unit?
1
What does the all or none law state?
When a motor unit is activated and the action potential is reached, all the fibres within the unit will contract - a muscle fibre can only be contracting or not
Impulses must be sufficient intensity to stimulate all the muscle fibres
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
What is a tetanic contraction?
A sustained muscle contraction caused by several stimuli that cause a muscle to contract in rapid succession
What is spatial summation?
When the strength of a contraction changes by altering the number and size of the muscle’s motor units that are recruited
What does PNF stand for?
Proprioceptive neuromuscular facilitation
What is the role of muscle spindles?
Proprioceptors that detect how far and how fast a muscle is being stretched to produce the stretch reflex
What happens once the muscle spindles detect the stretch?
They provide information to the CNS about how far and fast the muscle is being stretched
The CNS the sends an impulse back to the muscle telling it to contract - this triggers the stretch reflex
This action causes the muscle to contract to prevent overstretching
What is the role of golgi tendon organs?
To detect tension in a muscle telling
How do golgi tendon organs work?
During the isometric contraction in PNF, they detect the increase in muscle tension
They send inhibitory signals to the brain which allows the antagonistic muscle to relax and lengthen - autogenic inhibition
What is autogenic inhibition?
Where there is a sudden relaxation of the muscle in response to high tension
