Neurons pass information to one another through synapses. While the firing of an action potential (nerve impulse) is basically electrical, the communication between neurons is chemical. These chemicals cross over the synapse from one neuron and cause the other neuron to be excited or inhibited by altering the electrical activity in that neuron. However, the receiving neuron will only fire a nerve impulse if it is reaching the threshold for firing. If not, it will not pass the message along to the next neuron. This is known as the all-or-nothing event.
Myelin is a fatty layer that coats some cells. Small gaps in the myelin help nerve impulses move faster. Instead of passing down the entire length of the axon they can skip over the gaps.
Our brains are made up of two hemispheres, the right and the left hemispheres. There is an association between which hemisphere is dominant and whether you are right or left-handed. Most people are right-handed and their left hemisphere dominates over their hemisphere. However, left-handed individuals tend to be less lateralized. In other words, they are more likely to have both hemispheres involved in motor skills and language.
The nervous system can be divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (somatic and autonomic nervous systems). The autonomic system can be divided into the sympathetic and parasympathetic branches.
The endocrine system uses hormones in the bloodstream to chemically communicate with the rest of the body. The endocrine glands can influence moods, behavior, and even personality. Many of the endocrine glands are themselves influenced by the pituitary gland ("master gland"), which is in turn influenced by the hypothalamus in the brain.