what is reflex action

A reflex action is an involuntary and nearly instantaneous response to a stimulus. It is an automatic response that does not require conscious thought and is directed into the synapse in the spinal cord, rather than routing to the brain. Reflexes occur via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron, which evokes a target response. There are many different types of reflexes, but the most basic is called a simple reflex, which contains only one space where information in the spinal cord travels between two nerve cells, called neurons. The four parts of a monosynaptic simple reflex are a sensor, a sensory neuron, a motor neuron, and the muscle that creates an action. Reflexes are fine-tuned to increase organism survival and self-defense, such as the startle reflex, which provides an automatic response to an unexpected stimulus, and the feline righting reflex, which reorients a cats body when falling to ensure safe landing.