Fill in the Blanks A&P Stretch reflex unit 2Online version Unit 2 for A&P by Kirsten Storemski 1 neurons neurons fibers interneuron motor muscle sensory alpha center coordination spindle tension contraction directly posture specialized muscle center motor central muscle gamma central In the stretch reflex , sensory receptors are . They are a muscle fiber . Contractile ends are innervated by . These neurons can contract to pull on the of the fiber . This maintains of portion of spindle during muscle contraction . In the stretch reflex , the of the fiber is sensitive to tension . The sensory fiber synapses with which innervate the muscle in which the muscle spindle fiber is found . There is no in this reflex . Stretching of muscle will ultimately result in the of the same . This reflex is important in and .