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The brain is made up of billions of cells called neurons. Neurons are specialized to communicate with one another to make it possible for people to sense the world, think, move their bodies, and carry out their lives. As shown in Figure 4.6, neurons have distinct structures that set them apart from other cells and enable the communicative functions characteristic of neurons. Dendrites are branching receptors that receive chemical messages (called neurotransmitters) from other neurons that are translated into an electrical signal (Stiles, 2017). The axon is a long tube-like structure that extends from the neuron and carries electrical signals to other neurons. Neurons do not touch. Instead, there are gaps between neurons called synapses. Once the electrical signal reaches the end of the axon, it triggers the release of the neurotransmitter, which crosses the synapse to communicate with the dendrites of another neuron (Carson, 2014). This process of neural transmission is how neurons communicate with other neurons. Neurons also communicate with sensory and motor cells. Some axons synapse with muscle cells and are responsible for movement. The dendrites of some neurons synapse with sensory cells, such as those in the eyes or ears, to transfer sensory information such as vision and hearing (Gibb & Kovalchuk, 2018). Finally, axons are often coated with a fatty substance called myelin, which speeds the transmission of electrical impulses and neurological function.

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Figure 4.6 The Neuron