Carvell, PhD, PTUniversity
THE MOTOR UNIT
single alpha motoneuron (anterior horn
cell), its dendrites, and its axon are shown. Note the extensive distribution of the dendrites into ventral and intermediate gray and white matter of the lateral columns adjacent to the spinal gray. This is
the location of
a portion of the propriospinal
Nolte, Fig 10-7 p 224
S. Sherrington described the alpha motoneuron and its innervated muscle fibers as the
motor unit. The motor unit is the
functional unit of contraction in skeletal muscle. Normally, once an action potential is
conducted from the axon hillock to the muscle all the muscle fibers contacted by the axon collaterals will be activated; this
assumes the periphery is intact
and muscles are unfatigued.
Sherrington referred to the alpha motoneuron (anterior horn cell) as the final common pathway for all movements involving skeletal muscle.