<prompt> Motor supply to muscle spindle is through-AlphaBetaGammaDelta  <response>: Ans. is c i.e., Gamma Sensory innervation afferent of muscle spindle Two types of sensory nerve fibers afferent originate from the intrafusal fibers : -1 Annulospiral Primary ending are wound around the central region of both nuclear bag fiber and nuclear chain fiber. These are Aa or la fibers.2 Flower-spray Secondary endings innervate the peripheral parts ends of nuclear chain fiber. These are Ab or or II fibers.Motor innervation efferent of muscle spindle The peripheral part of both nuclear bag fiber and nuclear chain fiber are innervated by motor fibers which are Ag type also called y-motor neurons or fusimotor neuron or Lekcell efferents. g1 dynamic g-fibers innervate nuclear bag fiber and their terminals are called plate ending. g2 static - g - fibers innervate nuclear chain fibers and their endings are called trail ending. Ag fibers alter spindle sensitivity to stretch. y2 fibers alter the dynamic sensitivity, whereas g2 fibers alter the static sensitivity of stretch reflex. Neurons of Intrafusal fibers spindlesAfferent Sensory neuronsEfferent Motor neurons Aa Type Ia Ab Type II g-motor Ag 