Neuro-Muscular System Flashcards
What is the autonomic nervous system ?
Regulates the function of internal organs and controls some skeletal muscles
What does the sympathetic nervous system do in the neuromuscular system ?
Prepares the body for exercise
Fight or flight phase
What does the parasympathetic nervous system do in the neuromuscular system ?
Relaxes the body and slows down many high energy functions
Rest and relax phase
What are the 3 types of muscles fibres ?
Slow oxidative twitch (type I)
Fast oxidative glycolytic (type IIa)
Fast glycolytic (type IIx)
Describe slow twitch fibres
Slower contraction speeds than fast twitch
Better adapted to lower intensity/ longer duration exercise
Produce most of their energy aerobically
Have special characteristics that allow them to use oxygen more effectively
Describe fast twitch fibres
Have much faster contraction speed than slow twitch
Generate greater force of contraction
Fatigue quickly – used for short, intense bursts of effort.
Produce energy anaerobically
Type IIa (fast oxidative glycolytic):
More resistant to fatigue
Used in events where a longer burst of energy
Type IIx (fast glycolytic):
Fatigue quicker than type IIa
Used for highly explosive events
Characteristics of type 1 muscle fibres
(F) Contraction speed (meters per second) - Slow
(S) Motor neurone size - Small
(F) Motor neurone conduction capacity - Slow
(F) Force produced - Low
(F) Fatigability - Low
(S) Mitochondrial density - High
(S) Myoglobin content - High
(S) Capillary density - High
(F) Aerobic capacity - Very High
(F) Anaerobic capacity - Low
(F) Myosin ATPase/glycolytic enzyme activity - Low
Characteristics of type 2a muscle fibres
(F) Contraction speed (meters per second) - Fast
(S) Motor neurone size - Large
(F) Motor neurone conduction capacity - Fast
(F) Force produced - High
(F) Fatigability - Medium
(S) Mitochondrial density - Medium
(S) Myoglobin content - Medium
(S) Capillary density - Medium
(F) Aerobic capacity - Medium
(F) Anaerobic capacity - Medium
(F) Myosin ATPase/glycolytic enzyme activity - Medium
Characteristics of type 2x muscle fibres
(F) Contraction speed (meters per second) - Very fast
(S) Motor neurone size - Large
(F) Motor neurone conduction capacity - Fast
(F) Force produced - Very high
(F) Fatigability - High
(S) Mitochondrial density - Low
(S) Myoglobin content - Low
(S) Capillary density - Low
(F) Aerobic capacity - Low
(F) Anaerobic capacity - Very high
(F) Myosin ATPase/glycolytic enzyme activity - Very high
What is a motor unit ?
A motor neurone and a group of muscle fibres
What is a motor neurone ?
Nerve cells which transmit the brains instructions as electrical impulses to the muscles
What is a neuromuscular junction ?
Where the motor neurone and the muscle fibre meet
What is the all or none law ?
Where a sequence of impulses has to be of sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. If not, none of them contract.
What are the different types of summation ?
Wave summation (tetanic contraction)
Spatial summation
What is wave summation ?
Where there is a repeated nerve impulse with no time to relax
What is spatial summation ?
When the strength of a contraction changes by altering the number and size of the muscle’s motor units
Describe wave summation
The greater the frequency of stimuli, the greater the tension developed by the muscle.
If there are repeated nerve impulses, with no time to relax, this means calcium will build up in the muscle cell.
This produces a forceful, sustained, smooth contraction which is referred to as a tetanic contraction.
Describe spatial summation
Motor units within a muscle are activated at the same time but at different places on the neurone
By spreading out the contraction and relaxation, the muscle is able to sustain a continuous contraction over a period of time
Shares the workload and reduces fatigue.
Changes in strength of contraction is brought about by altering the number and size of motor units involved.
What is PNF ?
PNF is an advanced stretching techniques
One of the most effective ways to increasing range of motion
Contract
Relax
Antagonist
Contract
What is the method for PNF ?
Muscle is stretched to the limit
Stretch position is held for a few seconds with help
The muscle group contracts isometrically
Muscle relaxes
The muscle can be stretched further
What are muscle spindles ?
Very sensitive
Lie between muscle fibres
Often referred to as stretch receptors
Detect how far and fast a muscle is being stretched
What are Golgi tendons ?
