So, impulses are basically reactions from something else. So, in the brain, there are neurons, which are also known as brain cells. They have two main and really important parts, called the dendrite and the axon. The dendrite receives the impulse, either from the central nervous system (CNS) or from the peripheral nervous system (PNS). After this event, the axon transfers and carries the impulse away from the cell body. Also, the impulse travels through a little gap in between neurons called the synapse, before the impulse travels to the next neuron. And, remember, this process is not slow. This process occurs in a matter of milliseconds. Think about it. If you burn your hand from something really hot, you will react to that really fast as an impulse. Millions of neurons will react to that in just a second. That's why science is so cool. It has so many interesting topics and fascinating facts, like this. Anyways, I hope this helped you. Enjoy your day.