Neuromuscular system Flashcards
State 3 characteristics of fast twitch glycolytic (Type IIx) muscle fibres
High contraction speed
Large motor neurone size
Large muscle fibre diameter
High fatigability
Low mitochondrial density
Low myoglobin content
Low capillary density
Low aerobic capacity
Very high anaerobic capacity
State 3 characteristics of fast twitch oxidative (Type IIa) muscle fibres
High contraction speed
Large motor neurone size
Medium fatigability
Medium mitochondrial density
Medium myoglobin content
Medium capillary density
Medium aerobic capacity
Medium anaerobic capacity
State 3 characteristics of slow twitch (Type I) muscle fibres
Slow contraction speed
Small motor neurone size
Low fatigability
High mitochondrial density
High myoglobin content
High capillary density
Very high aerobic capacity
Low anaerobic capacity
What is the ‘All or None Law’?
Sequence of impulses either has sufficient intensity to stimulate all of the muscle fibres within a motor unit to contract
If not, none of them contract
What’s the difference between spatial summation and wave summation?
Spatial = contraction strength changes by altering the number and size of the muscle’s motor units
Wave = repeated nerve impulse with no time to relax / smooth sustained contraction occurs rather than twitches
What is tetanic contraction?
A sustained powerful muscle contraction caused by a series of fast repeating stimuli
What are the 2 types of proprioceptors involved in PNF?
Muscle spindles
Golgi tendon organs
How do each of the proprioceptors aid PNF?
Muscle spindles = detect how far a muscle is being stretched / produces the stretch reflex
Golgi tendon organ = detect levels of tension within a muscle and send these signals to the brain which allows the antagonist to relax and lengthen (autogenic inhibition)
Describe a motor unit
A motor neurone and its muscle fibres
One type of muscle fibre per motor unit
Each motor neurone branches / ends at the neuromuscular junction
