Question

What is the speed of message from human body part to brain?

and what is the speed of reply from brain to that part of body?

Answer 1

There are different neurons in our body that send signals with different speeds. Some myelinated neurons can send signals to the brain with speed of approximately 120 m/s (432 km/hr) and brain can response back to the body cells via motor neuron with the same speed. The speed in neurons ranges from 1 m/s to 120 m/s approximately.