Guillain-Barré syndrome (GBS) is an acute autoimmune demyelinating neuropathy of the peripheral nervous system. It often develops after a bacterial infection, where the immune system produces antibodies against bacterial surface antigens that structurally resemble gangliosides (lipids) on the myelin sheath of Schwann cells.
Describe how molecular mimicry after an infection can lead to the body's immune system mistakenly initiating and executing an autoimmune attack on the myelin sheath of peripheral neurones.
Describe how myelination by Schwann cells normally increases the speed of action potential conduction along a peripheral sensory neurone, and explain why demyelination in GBS patients leads to a significantly reduced conduction velocity.
Suggest and describe how a reduced frequency of action potentials reaching the presynaptic membrane of a motor neurone at a neuromuscular junction (NMJ) affects acetylcholine-mediated transmission and the subsequent contraction of the postsynaptic skeletal muscle fibre.
