A sweat gland begins secreting after an electrical impulse travels along a motor neurone. Damage removes patches of myelin from the axon, and the gland now responds later to the same stimulation.
Which statement explains the later response?
the exposed axon loses electrical insulation, so the impulse travels more slowly
the damaged axon develops extra synapses, so the impulse crosses more gaps
the damaged axon sends the impulse towards the CNS before it reaches the gland
the exposed axon carries the impulse chemically, so neurotransmitter must diffuse along it
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.