(a)[5]
Explain how the action of an opioid drug on the presynaptic membrane can stop pain impulses from being generated in the postsynaptic neurone.
(b(i))[2]
State two features of a spinal reflex, apart from the fact that it is fast.
(b(ii))[2]
In a spinal reflex, sensory and motor neurones are used. State where the cell body of a sensory neurone is found and where the cell body of a motor neurone is found.
(b(iii))[4]
Describe the roles of a sensory neurone and a motor neurone in a spinal reflex.