Neural Chemical Communication exercises

MONASH University Medicine, Nursing and Health Sciences

Neuromuscular Transmission  Unreliable Facts

Instructions: Identify and select the 3/10 correct sentences

  1. The neuromuscular junction is the synapse between a motor neuron and a muscle fibre where the motor neuron produces an Action Potential (AP) to transmit information to the muscle fibre.
  2. The motor neuron's AP at the axon terminal causes the release of acetylcholine (ACh) into the neuromuscular junction.
  3. The specialized postsynaptic region of the muscle cell is called the motor endplate and its anatomical specializations include are junctional folds which have a very high density of cholinergic receptors.
  4. Acetylcholine binds to muscarinic receptors at the end plate on the muscle fibre's membrane, known as the sarcolemma.
  5. The binding of acetylcholine to its receptors on the endplate membrane causes the influx of Ca++ and K+ and efflux of Na+, down their respective concentration gradients.
  6. The movement of ions through the chemically-gated cholinergic receptors on the sarcolemma produces a response called the End Plate Potential.
  7. The End Plate Potential triggers an Action Potential at the sarcolemma close to the endplate and this AP travels regeneratively along the sarcolemma and into the T-tubules, which are invaginations of the cell membrane.
  8. Acetylcholinesterase, an enzyme found at the active zones on the axon terminal at the neuromuscular junction, breaks down acetylcholine, terminating the signal.
  9. Botulinum toxin triggers an autoimmune response where antibodies attack acetylcholine receptors, leading to muscle paralysis.
  10. Myasthenia gravis is an autoimmune disorder where the MYAS-G molecules inhibit the release of acetylcholine, causing muscle weakness.