NMJ

• NMJ - point where motor neurone meets a skeletal muscle fibre
• NMJ

  • Always uses Ach
  • Postsynaptic membrane folded into many clefts that store acetylcholinesterase
• NMJ

  • Always uses Ach
  • Postsynaptic membrane folded into many clefts that store acetylcholinesterase
  • Postsynaptic membrane has more receptors
  • Impulses are always excitatory
  • Endpoint for the AP
  • Connects motor neurone to muscle
• Neurone synapse

  • Many different neurotransmitters used
  • Membrane smooth with acetylcholinesterase found in central cleft
  • Postsynaptic membrane has fewer receptors
  • Impulses can be excitatory or inhibitory
  • A new AP is generated in the next neurone
  • Connects two neurones
• Describe how the release of Ach into a NMJ causes the cell membrane of a muscle fibre to depolarise (3)

  • Movement by diffusion
  • Binding to receptors on postsynaptic membrane
  • Causing sodium channels to open
• When an AP arrives at the synaptic cleft it results in the secretion of Ach into the synaptic cleft. Explain how (3)

  • Depolarisation of presynaptic membrane
  • Ca2+ channels open
  • Vesicles fuse with presynaptic membrane