Answer:
Upper motor neurons: they are the motor cells of cerebral cortex and subcortical centres whose axons constitue the pyramidal and extra-pyramidal tracts (which then descend to end around the motor nuclei of cranial nerves in brainstem and anterior horn cells of the spinal cord)
Lower motor neurons: they are the cells of motor nuclei of cranial nerves and anterior horn cells of spinal cords, and their axons which constitute the motor fibres of the peripheral nerves that terminate in the motor end plate of striated muscles.