The brain isn’t just made of neurons. While there are about 100 billion neurons in an adult human brain, there are around ten times as many supportive cells. These cells include astrocytes, microglia, and oligodendrocytes. These cells keep the brain clean, healthy, and well-supplied with oxygen and nutrients.
Neurons are the primary communication cell in your brain, and the most special part about the nervous system. They can come in all shapes and sizes, and specialize in various jobs such as movement, memory, and mood. Different neurons do different jobs in the brain and body: pyramidal neurons process information, whereas motor neurons send messages to your muscles for movement. Neurons form a synapse, or a communication bridge, with themselves and Astrocytes
Astrocytes, also known as astroglia, are the main supportive cell type of the brain. Astrocytes help to clear waste or excess neurotransmitters from between neurons and help to regulate blood flow to the brain. Astrocytes and neurons talk to each other constantly. They form thousands of contacts with neurons, watching over synapses to ensure their proper function. Dysfunctional crosstalk between astrocytes and neurons has been implicated in addiction, depression, dementia and other neurological disorders.
Oligodendrocytes are type of glial cell, similar to astrocytes. Astrocytes and oligodendrocytes can even transform into each other when needed. Oligodendrocytes are the insulators of the brain, wrapping neuronal axons with thick, fatty blankets called myelin that help protect them and increase their upload and download speeds, like rubber wrapped around a wire. Losing myelin is devastating. Myelin deficiency is associated with diseases and disorders like Multiple Sclerosis and Schizophrenia.
Microglia do the dirty work in the brain. Microglia are a typical brain cell: they come from macrophages, the body’s primary phagocytic immune cell. Phagocytic immune cells phagocytize, or engulf and swallow trash, foreign particles or dying cells. In the brain, microglia prune synapses like a gardener trims an overgrown bush. This is essential to avoid a hyper-connected brain. But when microglia become hyperactive, they can over-trim neurons and cause problems in the brain.