A monosynaptic reflex is a simple neural pathway that involves only one synapse between a sensory neuron and a motor neuron. This type of reflex occurs quickly, allowing for immediate responses to stimuli, such as when you touch something hot and quickly pull your hand away. The most common example of a monosynaptic reflex is the patellar reflex, or knee-jerk reaction. When the patellar tendon is tapped, sensory receptors send a signal to the spinal cord, which directly activates the motor neuron to contract the quadriceps muscle, causing the leg to kick out.