Question

why it pains when someone slaps me.what happens to our veins?

Answer 1

Because when someone slaps u your motor neurons reacts very fast to respond u

Answer 2

nerves all over the body meet in a bundle in the spinal cord on their way to the brain. reflex arcs are formed in this spinal cords itself although the information input also goes on to reach the brain.so it is in the absence of true thought processes . however even after complex neuron networks have come into existence, reflex arcs continue to more efficient for quick responses. these are the reasons. i have explained in brief manner. hope it helps.