<P> Deforming the corpuscle creates a generator potential in the sensory neuron arising within it . This is a graded response: the greater the deformation, the greater the generator potential . If the generator potential reaches threshold, a volley of action potentials (nerve impulses) are triggered at the first node of Ranvier of the sensory neuron . </P> <P> Once threshold is reached, the magnitude of the stimulus is encoded in the frequency of impulses generated in the neuron . So the more massive or rapid the deformation of a single corpuscle, the higher the frequency of nerve impulses generated in its neuron . </P> <P> The optimal sensitivity of a lamellar corpuscle is 250 Hz, the frequency range generated upon finger tips by textures made of features smaller than 200 micrometres . </P> <P> The knee jerk is the popularly known stretch reflex (involuntary kick of the lower leg) induced by tapping the knee with a rubber - headed hammer . The hammer strikes a tendon that inserts an extensor muscle in the front of the thigh into the lower leg . Tapping the tendon stretches the thigh muscle, which activates stretch receptors within the muscle called muscle spindles . Each muscle spindle consists of sensory nerve endings wrapped around special muscle fibers called spindle fibers (also called intrafusal fibers). Stretching a spindle fiber initiates a volley of impulses in the sensory neuron (a I-a neuron) attached to it . The impulses travel along the sensory axon to the spinal cord where they form several kinds of synapses: </P>

Where are pressure receptors located in the skin