 See how quickly I moved my hand from the hot stove? Our bodies have a system in place which enables us to react really quickly, called reflex reactions. Reflex reactions are immediate unconscious responses to a stimulus that provides us with protection and facilitates our survival. From our videos on the nervous system and nerve cells, you should already know about the stimulus receptor, sensory neuron, central nervous system, motor neuron effector pathway and how sensory neurons, motor neurons and relay neurons differ from one another. In this video, we are going to look at what happens in reflex reactions. Touch a boiling plate, face to face with a lion, eye reacting to bright light, you want a fast reaction. When your safety demands a quick response, the signals may bypass the brain and be acted upon as soon as they reach the spinal cord. These shorter pathways are called reflex arcs. Reflex arcs are built in or innate behaviours, and we all behave in the same way. Even though the brain is bypassed for the immediate response, the nerve message is still passed onto the brain, so that you can think about whether any further action is needed. So the pathway has been cut down by speeding up the central nervous system aspect. The message reaches the spinal cord and heads straight back out, down the motor neuron to produce a response. See what happens when you touch a hot object. There are two types of reflex. Simple reflexes, like we have seen already, where the brain is not aware of the initial response, this aids your survival. You can also have conditioned reflexes. These involve prior thought or learning, and your body responds subconsciously because of this. Pavlov's dogs is an example of conditioned learning. During his experiments, Pavlov rang a bell immediately before feeding the dogs. He found that after a while, the dogs would produce saliva just on hearing the bell without food being provided. Pavlov called this a learned response, which does not involve subconscious thought and is a conditioned reflex. So from this video, you should know how reflex reactions work, and how they protect the body from damage. Everyone does them and have no conscious control of what is happening, but your brain can then choose to override the initial response or act further, because this message does get sent onto the brain as well.