Every time that I teach Introduction to Psychology, I notice a negative reaction to the fact that the second chapter in almost every introductory book is about the brain and nervous system. Memory, learning, problem solving, personality, attitudes, perceptions, and circadian rhythm are just a few of the processes that live in the brain. Your text does an excellent job of both describing and illustrating the various parts of the neuron.
All nervous impulses are of the same strength.
If the stimulus is a brick, the affected tissue sends out a chemical message, called by some researchers substance P, that causes the neurons to keep firing as soon as they recover from the refractory period. Also, a greater number of neurons are involved. In the disease multiple schlerosis, the myelin disintegrates in a variety of places, causing trouble walking and general weakness. In addition to the structure of the neuron itself, we have to look at the role of neurotransmitters. Some of these chemicals are excitatory, some are inhibitory, and some can be either, depending upon the location of the receptor.