neuromuscular system Flashcards
Definition of sympathetic
prepares our body for exercise
flight or fight response
Definition of parasympathetic
relaxes the body
rest
Description of type 1 muscle fibres
- slower contraction speed
- better adopted to lower intensity exercise
- produce energy aerobically
- example: marathon/triathlon
Description of type 2a muscle fibres (slow oxidative glycolytic)
- generate greater force of contraction
- faster contraction speed
- fatigue quickly
- produce energy anaerobically
- use oxygen but not lots
- example: 1500m run/400m swim
Description of type 2x muscle fibres (fast glycolytic)
- provides greatest muscle contraction
- fatigue quickly
- used for explosive events
- short burts of energy
- example: 50m swim/100m sprint
Effect of training on muscle fibres
- fibre types are genetically determined
- can increase the size of the muscle fibres through training (hypertrophy)
- results in greater strength of the muscle
Definition of motor unit
consists of a motor neurone and muscle fibres
only 1 type of muscle fibre can be found in 1 motor unit
What does each motor neurone have
neuromuscular junction
All or none law
- once the motor neurone stimulates the muscle fibres either all of them work or none of them work
- it is not possible for a motor unit to partially contract
- a minimum amount of stimulation is called ‘threshold’
Definition of wave summation
repeated nerve impulses with no time to relax so a smooth sustained contraction occurs rather than twitches
Definition of tetanic contraction
most forceful contraction
Why is calcium needed in a muscle
to contract the muscle
* each time the nerve impulse reaches the muscle cell calcium is released
Definition of spatial summation
addition of impulses recieved at different places on the neurone
When does spatial summation occur
nerve impulses recieved at the same time at difference places on the neurone
What does PNF stand for
proprioreceptive neuromuscular facilitation
What is PNF
advanced muscle stretching technique
contract - relax- antagonist - contract
What do muscle spindles do
- provide information (excitatory signals) to the CNS about how fast and how far the muscle is being stretched
- CNS sends impulse to the muscle telling it to contract, triggering the stretch reflex
- reflex action causes the muscle to contract to prevent overstretching, reducing the risk of injury
What do the golgi tendons do
- when the muscle is contracted isometrically in PNF they sense the increase in muscle tension
- they send inhibitory signals to the brain to override the stretch reflex
- allows the antagonist muscle to relax and lengthen (autogenic inhibition)
Functional characteristics of type 1 (slow twitch) muscle fibres
- slow contraction speed
- slow motor neurone conduction capacity
- low force produced
- low fatigability
- high aerobic capacity
- low anaerobic capacity
- low myosin ATPase capacity
Structural characteristics of type 1 (slow twitch) muscle fibres
- small motor neurone size
- high mitochondrial density
- high myglobin content
- high capillary density
Functional characteristics of type 2 a (fast oxidative glycolytic) muscle fibres
- fast contraction speed
- fast motor neurone conduction capacity
- high force produced
- medium fatigability
- medium aerobic capacity
- high anaerobic capacity
- high myosin ATPase capacity
Structural characteristics type 2 a (fast oxidative glycolytic) muscle fibres
- large motor neurone
- medium mitochondrial density
- medium myglobin
- medium capillary density
Functional characteristics of type 2 x (fast glycolytic) muscle fibres
- fast contraction speed
- fast motor neurone conduction capacity
- high force produced
- high fatigability
- low aerobic capacity
- high anaerobic capacity
- very high myosin ATPase capacity
Structural characteristics of type 2 x (fast glycolytic) muscle fibres
- large motor neurone size
- high mitochondrial density
- low myoglobin density
- low capillary density
