The Neuromuscular System - Applied Anatomy and Physiology (Paper 1) Flashcards
What is the neuromuscular system
Where the muscles and nervous system work together to allow movement
When do changes in the neuromuscular system take place
Before,during and after the exercise
What are the types of muscle fibres
Slow oxidative (type 1 or slow twitch fibres)
Fast oxidative glycolytic (type 2a)
Fast glycolytic (type 2b)
What are slow twitch fibres
-slower contraction speed than fast twitch fibres
-better adapted to lower intensity exercise
-Produce most of their energy aerobically
What are fast twitch fibres
-faster contraction speed than slow twitch fibres
-generate much greater force of contraction
-fatigue very quickly
-produce most energy anaerobically
-two types 2a 2b
What are type 2a fibres
-fast oxidative glycolytic
-fibres more resistant to fatigue than 2b
-used for 1500m in athletics where a longer burst of energy is needed
What are type 2b fibres
-Fast glycolytic
-fibres fatigue much quicker than type 2a
-used for highly explosive event e.g. 100m
What is the contraction speed of each of the muscle fibres
Type 1: Slow
Type 2a: Fast
Type 2b: Fast
What is the motor neurone size in each of the muscle fibres
Type 1: Small
Type 2a: Large
Type 2b: Large
What is the motor neurone conduction capacity in each fibre
Type 1: Slow
Type 2a: Fast
Type 2b: Fast
What is the force produced in each of the muscle fibres
Type 1: low
Type 2a: High
Type 2b: High
What is the fatigability on each if the muscle fibres
Type 1:low
Type 2a:medium
Type 2b:High
What is the mitochondrial density in each if the muscle fibres
Type 1: high
Type 2a: medium
Type 2b: low
What is the myoglobin content on each if the muscle fibres
Type 1: High
Type 2a: medium
Type 2b: low
What is the capillary density in each muscle fibre
Type 1:high
Type 2a:medium
Type 2b:low
What is the aerobic capacity on each muscle fibre
Type 1:very high
Type 2a:medium
Type 2b:low
What is the anaerobic capacity of each muscle fibre
Type 1: low
Type 2a: high
Type 2b: very high
What is the glycolytic enzyme activity of each muscle fibre
Type 1: low
Type 2a: high
Type 2b: very high
What is the fibre type determined by
Genetics, however it is possible to increase the size of muscle fibres through training (hypertrophy)
What are muscle fibres grouped into
Motor units
What does a motor unit consist of
-Motor neurone
- and it’s muscle fibre
How many types of muscle fibres can be found in a motor unit
Only one muscle fibre can be found in one particular motor unit
What is a neuromuscular junction
Where the motor neurone and the muscle fibre meet
What is the all or none law
Once the motor unit stimulates the muscle fibres either all of them contract or none of them contract
Is it possible for a motor unit to partially contract
No, because the threshold has not been met
What is the minimum amount of stimulation to start a contraction called
A threshold
What happens if the sequence of impulses is equal to or more than the threshold
All the muscle fibres in a motor unit will contract
What happens if the sequence of impulses is less than the threshold
Then no muscle action will occur
What is wave summation
Repeated nerve impulses stimulating the muscle with no time to relax
Results in a greater force of contraction
What happens if calcium builds up in a muscle cell
This produces a forceful, sustained, smooth contraction also known as a tetanic contraction
Define tetanic contraction
A sustained muscle contraction caused by a series of fast repeating impulses.
What is spatial summation
- the recruitment of additional and bigger motor units within a muscle to develop more force.
- occurs when impulses are received at the same time at different places on the neurone.
Define spatial summation
When the strength of a contraction changes by altering the number and size in the motor units
What does PNF stand for
Proprioceptors neuromuscular facilitation
What is PNF
An advanced stretching technique considered to be one of the most effective forms of flexibility training for increasing range of motion
What are the proprioceptors that make PNF possible
Muscle spindles
Golgi tendon organs
Define muscle spindles
Proprioceptors that detect how far and how fast a muscle is being stretched and produce the stretch reflex
Define Golgi tendon organs
Proprioceptors that are activated when there is tension in a muscle
Define isometric contraction
Where there is tension in a muscle but no visible movement
Define autogenic inhibition
Where there is a sudden relaxation of the muscle in response to high tension. The receptors involved in this process are Golgi tendon organs
What is the first step to PNF
- Individual performs passive stretch. They extends the leg until tension is felt. This is done by the help of a partner
- If the muscle is being stretched too far then a reflex should happen
What is the second step of PNF
Isometric contraction - Leg is held still
What is the third step of PNF
- leg is lifted again and the golgi tendon organs are responsible for the antagonist muscle relaxing which means the leg stretches further
- process is repeated until no more gains are possible
What is the role of the Golgi tendon organs in PNF
send inhibitory signals which allows the antagonist muscle to relax and lengthen and delay the stretch reflex. This is known as autogenic inhibition.
