Neurons

Both newborn and adult brains contain approximately 100 billion neurons. Despite accounting for only about 2% of total body mass, the brain uses approximately 20% of the body's energy. Approximately 20% of the body's blood supply is directed to the brain to support its high energy demand. Neuronal function is fundamentally an electrical communication process involving thresholds, inhibition, facilitation, and summation. Each neuron has a distinctive structure consisting of a cell body, an axon, boutons at the axon's end, and dendrites. The axon is a long arm extending from the neuron's cell body, terminating in small filaments called boutons. Dendrites are the receiving structures of a neuron, positioned adjacent to the axon terminal of the preceding neuron.