Knee-Jerk Reflex: How the Brain Processes Sensory Input

During a knee-jerk reflex, the nerve impulse is received by the sensory neuron. The sensory neuron is responsible for transmitting the information about the stimulus (in this case, the tap on the patellar tendon) to the central nervous system. The central nervous system then sends a signal to the motor neuron, which causes the contraction of the quadriceps muscle, resulting in the knee-jerk reflex.