Nerve cells relay messages, or transfer information to each other, by producing an electrochemical signal called the "action potential" . This signal travels down a part of the nerve cell called the axon, which is like a wire that carries the signal to other nerve cells. On average a nerve cell sends a signal at about 50 meters per second, which is over 100 miles an hour!

Depending on a number of factors, signals can be sent even faster. One important factor is how myelinated the axon is .

Myelin is a fatty substance that acts as an electrical insulator, increasing the speed at which the signal is sent. A highly myelinated nerve cell can send a signal at up to 120 meters per second, or nearly 270 miles per hour, quite a bit faster than an airplane taking off! These quick speeds are the basis for everything the brain does, from making sense of what your eyes see to deciding what you're going to have for lunch.

The nervous system can relay messages about at a speed of 150 meters/second. For context, a car is only moving at 26.8 meters per second when driving 60 miles per hour. When you shoot a bullet, it is close to 350 meters per second. An interesting thought then is which sense is our fastest sense?

The human nervous system can send signals that travel faster than 200 miles per hour, which is more than 328 feet per second! If our nervous system were slower, we would not be able to react to a car suddenly braking in front of our car, or catch a ball before it hits our faces.

That depends on the nervous system. Myelinated neurons can transmit over speeds of tens of meters per second, typically around 50 m/s. This is unique to vertebrates; invertebrate animals need to increase the diameter of the neuron. That said, giant squid are able to get signals moving very fast as well, just by having nerve cells large enough to be visible to the naked eye. There is no simple answer.