The ways in which the words can be meaningfully combined is defined by the language's syntax and grammar. The actual meaning of words and combinations of words is defined by the language's semantics.
A nerve impulse is an electrical signal that travels along an axon. There is an electrical difference between the inside of the axon and its surroundings, like a tiny battery. When the nerve is activated, there is a sudden change in the voltage across the wall of the axon, caused by the movement of ions in and out of the neuron.
This essentially happens by means of the nerve impulse. A nerve impulse is the transmission of a coded signal from a given stimulus along the membrane of the neuron, starting in the point where it was applied. Nerve impulses can pass from one cell to another, thus creating a chain of information within a network of neurons. Two types of phenomena are involved in processing the nerve impulse: electrical and chemical.