Skeletal Muscle (HL) (HL IB Biology)

• Skeletal muscle contracts when it receives an impulse from a motor neurone via the neuromuscular junction
  • Neuromuscular junctions work in a very similar way to synapses
  • They are located between a motor neurone and a muscle cell
• The collection of a motor neurone, the skeletal muscle fibers, the neuromuscular junctions between the neurone and the muscle fibres form a motor unit
• There are multiple neuromuscular junctions spread across several muscle fibres within the motor unit and this varies the intensity of muscle contraction
  
  • During a low intensity muscle contraction, a low number of motor units are activated
  • For a high intensity contraction, more motor units receive impulses

Motor Unit Diagram

The motor unit of skeletal muscle consists of a motor neurone, muscle fibres, and neuromuscular junctions