1.3 Neuromuscular system Flashcards
Paper 1
What are slow twitch fibres?
Type 1
Slow contraction speed
Lower intensity exercise
produce energy aerobically
What are Fast twitch fibres?
Type 2a
Type 2x
Fatigue quickly
used for short intense burst of effort
Anaerobically
What are the characteristics of Type 1 muscle fibres?
Slow contraction speed
Small motor neurone size
Slow motor neurone conduction
Low force produced
Low fatiguability
High mitochondrial density
High myoglobin content
Very High aerobic capacity
Low anaerobic capacity
Low ATP activity
What are the characteristics of Type 2a muscle fibres?
Fast contraction speed
Large motor neurone size
Fast motor neurone conduction capacity
High force produced
Medium fatiguability
Medium mitochondrial density
Medium myoglobin content
Medium capillary density
Medium aerobic capacity
High Anaerobic capacity
Low ATP
What are the characteristics of Type 2x fibres?
Fast contraction speed
Large motor neurone
Fast motor neurone conduction capacity
High force produced
High fatiguability
Low mitochondrial density
Low myoglobin content
Low capillary density
Low aerobic capacity
Very High Anaerobic capacity
Very High ATP
What is the All of None Law?
When a motor neurone stimulates the fibres all of them contract or none of them will
If sequence of impulses is equal or more than the threshold all muscle fibres will contract
If sequence of impulses is less than the threshold then there will be no contraction
How can you increase the strength of a contraction?
Wave summation
Spatial summation
What is wave summation?
When repeated activation of Moto neurone simulating a muscle fibre resulting in a greater force of contraction
Each time a nerve impulse reaches the muscle cell, calcium is released
Why is calcium is needed?
Needed for the muscle to contract
How does calcium build up?
If there is a repeated nerve impulses with no relax time causing a tetanic contraction
What is a tetanic contraction?
Forceful, sustained, smooth contraction
What is Spatial Summation?
It is the recruitment of additional bigger motor units within a muscle to develop more force
Occurs when impulses are received at the same time at different places on the neurone
PNF
What 2 proprioceptors?
Muscle spindles
Golgi tendons
What are muscle spindles?
Between skeletal muscle fibres
Provide information to CNS about how fast & far a muscle is being stretched
CNS sends impulses back to muscle telling it to contract
Triggers stretch reflex
Reflex action causes muscle to contract to prevent over stretching reducing the risk of injury