Brain cell

Brain cell
Illustration of a neuron, microtubules shown as they enter the axon, and seen enclosed in a myelin sheath.
Anatomical terms of microanatomy [edit on Wikidata]

Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges, blood vessels, and ducts. The two main types of cells in the brain are neurons, also known as nerve cells, and glial cells, also known as neuroglia.^[1] There are many types of neuron, and several types of glial cell.

Neurons are the excitable cells of the brain that function by communicating with other neurons and interneurons (via synapses), in neural circuits and larger brain networks. The two main neuronal classes in the cerebral cortex are excitatory projection neurons (around 70-80%) and inhibitory interneurons (around 20–30%).^[2] Neurons are often grouped into a cluster known as a nucleus where they usually have roughly similar connections and functions.^[3] Nuclei are connected to other nuclei by tracts of white matter.

Glia are the supporting cells of the neurons and have many functions not all of which are clearly understood, but include providing support and nutrients to the neurons. Glia are grouped into macroglia – astrocytes, ependymal cells, and oligodendrocytes, and much smaller microglia which are the macrophages of the central nervous system. Astrocytes are seen to be capable of communication with neurons involving a signalling process similar to neurotransmission called gliotransmission.^[4]