TOPIC 3: Lesson 1 - Sympathetic/Parasympathetic NS; Types of muscle fibres. Flashcards
What are the three main types of muscle fibres?
Type 1 - Slow Oxidative (SO)
Type IIa - Fast Oxidative Glycolytic (FOG)
Type IIb - Fast Glycolytic (FO)
What are the features of Type 1 muscle fibres?
- High numbers of mitochondria
- High levels of myoglobin
- High levels of fat stores
- High levels of oxidative enzymes
- High capillary density
- Slow to fatigue
- Low levels of force production
What are the features of Type IIa muscle fibres?
- Fast speeds of contractions
- High PC stores
- High level of force production
- Quick to fatigue
What are the features of Type IIb muscle fibres?
- Very fast speeds of contractions
- Very high PC stores
- Very high levels of force production
- Very quick to fatigue
What is the motor unit?
- A motor unit consits of one motor neuron and all the muscle fibres it stimulates.
What is meant by the ‘all or none’ rule?
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 is meant by ‘wave summation’ ?
When another stimulus is applied to a muscle before the previous relaxation period is complete, resulting in a stronger contraction.
What is meant by ‘tetanic contraction’?
A sustained muscle contraction cause by a series of fast repeating stimuli during wave summation.
What is meant by ‘spatial summation’?
When the strength of a contraction change by altering the number and size of the muscles motor units.
