Neuromuscular System Flashcards
What is the autonomic nervous system?
- Regulates the functions of our internal organs, such as the heart
- Controls some of our skeletal muscles
What is the neuromuscular system?
Where the nervous system and the muscles work together to allow movement
What do changes in the neuromuscular system do?
- Prepare the body for exercise
- Allow for the changing demands of different intensities of exercise
What are the sympathetic and parasympathetic systems part of the nervous system?
- Part of the peripheral nervous system
- Role is to transmit information from the brain to different parts of the body to adjust for exercise
What does the sympathetic nervous system do?
Prepares the body for exercise and is often referred to as the ‘fight or flight response’
What does the parasympathetic nervous system do?
Relaxes the body and slows down many high energy functions, often explained by the phrase ‘rest and relax’
What are the main types of muscle fibres?
- Slow oxidative (type I) (slow twitch)
- Fast oxidative glycolytic (type IIa)
- Fast glycolytic (type IIb)
What type of muscle fibre will elite endurance athletes have more of?
Slow twitch fibres in leg muscles
What are slow twitch fibres?
- Type I
- Slow contraction speed
- Better adapted to low intensity exercise (long-distance running)
- Produce most of their energy aerobically (using oxygen)
What are fast twitch fibres?
- Type II
- Fast contraction speed
- Generate greater force of contraction
- Fatigue quickly (used for short, intense bursts of energy)
- Produce most of their energy anaerobically (without oxygen)
What are the two types of fast twitch fibres?
- Type IIa (fast oxidative glycolytic)
- Type IIb (fast glycolytic)
What are fast oxidative glycolytic fibres?
- Type IIa
- More resistant to fatigue (used for 1500m events)
- For longer bursts of energy
What are fast glycolytic fibres?
- Type IIb
- Fatigue fastest
- Used for highly explosive events (100m sprints)
What is hypertrophy?
Where the muscle has become bigger and stronger
What is the motor unit?
A motor neurone and its muscle fibres
What are motor neurones?
Nerve cells which transmit the brains instructions as electrical impulses to the muscles
What is the neuromuscular junction?
Where the motor neurone and muscle fibres meet
How many types of muscle fibres can be found in one particular motor unit?
One
Where are the neuromuscular junctions?
At the end of branches off of each motor neurone
What are muscles made up of?
Many motor units varying in size
How many muscle fibres will a large muscle (gross motor control) have?
Has motor units with a motor neurone feeding hundreds of fibres
What is the ‘all or none’ law?
Where a sequence of impulses has to be of a sufficient intensity to stimulate all of the muscle fibres in a motor units in order for them to contract (if not, none of them contract)
What is the ‘threshold’ in the all or none law?
A minimum amount of stimulation required to start a contraction
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
What is a tetanic contraction?
A sustained muscle contraction caused by a series of fast repeating stimuli
What happens each time a nerve impulse reaches a muscle cell?
Calcium is released
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 the impulses are received at the same time at different places on the neurone (which add up to fire the neurone)
What is the PNF (proprioception neuromuscular facilitation)?
An advanced stretching technique, one of the most effective forms of flexibility training for increasing a range of motion
What are muscle spindles?
- Very sensitive proprioceptors
- Detect how far and how fast a muscle is being stretched
- Produce the stretch reflex
- Provide information to the central nervous system (how fast and far the muscle is being stretched)
What is the golgi tendon organs?
- Found between the muscle fibre and tendon
- Signal information about the load or force being applied to a muscle
- Activated when there is tension in the muscles
- Detect levels of tension in a muscle
What are muscle spindles and golgi tendon organs types of?
Proprioceptors
What are isometric contractions?
Where there is tension in a muscle but no visible movement
What is autogenic inhibition?
Where there is a sudden relaxation of the muscle in response to high tension (golgi tendon organs involved in this)
What is autogenic inhibition?
When the muscle is contracted isometrically in PNF, they sense the increase in muscle tension and send inhibitory signals to the brain which allows the antagonist muscle to relax and lengthen
