Neuromuscular Flashcards
What are the two important proteins involved in muscle contraction?
Myosin (thick filaments), and Actin. Troponin (which binds calcium and moves Tropomyosin) and Tropomyosin also involved.
How many neurones innervate a muscle fibre? How many fibres can a neuron innervate?
One muscle fibre, innervated by one neuron. One neuron can innervate many muscle fibres.
What is a motor unit?
One motor neuron and all the muscle fibres it innervates.
In one motor unit, how many different muscle fibre types are there?
One motor unit always innervates one type of muscle fibre.
What is spatial summation?
Increasing force by increasing the number of active motor units.
What is temporal summation?
Increasing the frequency of contraction within a motor unit.
What is ‘The Size Principal’? (Henneman)
It suggests that the smallest motor units (slow fibres) are recruited first, gradually working up to larger motor unit (fast twitch). Motor unit “recruitment”.
What is Muscle fatigue?
Muscle should produce same force first time, as the 100th time it contracts. If it doesn’t, it may be pathological.
What are the 3 types of muscle fatigue?
Central, Neuromuscular and Peripheral.
Explain Central Muscle Fatigue
“Hitting the Wall”. Based on increase in 5-HT in brain during exercise. Lethargy, loss of drive, lack of action potentials etc.
Explain Neuromuscular Muscle Fatigue
Many types, but can be depletion of NT (e.g. Tetanus), Post synaptic receptors (e.g. Myasthenia Gravis).
Explain Peripheral Muscle Fatigue
Depletion of Muscle metabolites (e.g. glycogen, ATP), or accumulation of metabolites (e.g. Lactic acid, ammonia)
