Neuromuscular system Flashcards
What does the autonomic nervous system do
Regulates the function of our internal organs and controls skeletal muscles.
What are the sympathetic and parasympathetic systems part of and what do they do
Peripheral nervous system and they transmit information from the rain to the parts of the body that need adjusting in preparation for excersise.
What does the sympathetic nervous system
Prepares the body for excersise and is refered to as ‘flight or fight response’
What does the parasympathetic nervous system do
Relaxes the body and slows down high energy functions
What are the three types of muscle fibres
- Slow oxidative (type I) (slow twitch
- Fast oxidative glycolytic (type IIa)
- Fast glycolytic (type IIb)
Fast twitch IIa have…
Fast contraction speed, produce energy anaerobically, large motor units, medium mitochondrial density, medium fatigability
Slow twitch have….
Slower contraction speed, produce energy aerobically, small motor units, high mitochondrial density, low fatigability
Fast twitch IIb have…
Fast contraction speed, produce energy anaerobically, large motor units, low mitochondrial density, high fatigability
What does a motor unit consist of
Motor neurone and its muscle fibres
What do muscle fibres do
Work with the nervous system so that a contraction can occur
What does the motor neurone do
Transmits the nerve impulse to the muscle fibre
What does each motor neurone have at the end
End of their branches there is a neuromuscular junction on the muscle fibre.
What is the all or none law
Once the motor neurone stimulates the muscle fibres, either all of them contract or none of them contract. It is not possible for a motor unit to partially contract.
How are slow/fast twitch motor units chosen
The brain will recruit the correct motor unit based on the excersise. Such as if a greater force of contraction is needed fast twitch units are chosen.
How to increase the strength of contraction
Frequency (Wave summation + Spatial summation)
Amount of motor units
Recruting differenet types of motor units (slow+fast)
What is wave summation
Where there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction occurs, rather than twitches.
How does the frequency of stimuli affect wave summation
The greater the frequency the greater tension is developed. Each time the nerve impulse reaches the muscle cell calcium is released which is required for a muscle contraction
What is a tetanic contraction
A sustained muscle contraction caused by a series of fast repeating stimuli
What is spatial summation
When the strength of a contraction changes by altering the number and size of the muscles motor units.
When does spatial summation occur
When impulses are received at the same time at different places on the neurone which add up to fire the neurone
What does PNF stand for
Proprioceptive neuromuscular facilitation
What is PNF
An advanced stretching technique including the CRAC technique - contract, relax, antagonist, contract.
What are the regulatory mechanisms in PNF
Proprioceptors such as muscle spindles, golgi tendon organs
What do proprioceptors do
Inform the body of the extent of movement that has taken place
What are muscle spindles
Sensitive proprioceptors that lie between skeletal muscle fibres.
Why are muscle spindles often called stretch receptors and what is the process in the stretch reflex
Often called stretch receptors as they provide information to CNS about the muscle. This is then sends an impulse back telling the muscle to contract triggering the stretch reflex
What does the stretch reflex prevent
Causes the muscle to contract preventing overstretching and injury
What are golgi tendon organs
Found between muscle fibre and tendon detecting tension in the muscle.
What is the autogenic inhibition
When contracting isometrically Golgi tndon organs sense the increase in muscle tension and send inhibitory signals to the brain allowing the antagonist to relax and lengthen
