Current research is uncovering important new roles for glia in brain function. Researchers have known for a while that glia transport nutrients to neurons, clean up brain debris, digest parts of dead neurons, and help hold neurons in place. The brain contains at least ten times more glia than neurons. In the brain, the glia that make the sheath are called oligodendrocytes, and in the peripheral nervous system, they are known as Schwann cells. This sheath is made by specialized cells called glia. Many axons are covered with a layered myelin sheath, which accelerates the transmission of electrical signals along the axon. When neurons receive or send messages, they transmit electrical impulses along their axons, which can range in length from a tiny fraction of an inch (or centimeter) to three feet (about one meter) or more. The dendrites are covered with synapses formed by the ends of axons from other neurons. Synapses are the contact points where one neuron communicates with another. The axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals.ĭendrites extend from the neuron cell body and receive messages from other neurons. The cell body contains the nucleus and cytoplasm. Each mammalian neuron consists of a cell body, dendrites, and an axon. The mammalian brain contains between 100 million and 100 billion neurons, depending on the species. The brain is what it is because of the structural and functional properties of interconnected neurons. Excitatory synapses terminate on dendritic spines, tiny protrusions from the dendrite with a high density of neurotransmitter receptors. The dendrite of a large pyramidal cell receives signals from about 30,000 presynaptic neurons. Dendrites extend from the neuron cell body and receive messages from other neurons. Dendrites provide an enlarged surface area to receive signals from axon terminals of other neurons. The axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals. Most neurons have a cell body, an axon, and dendrites. Neurons are cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.

Kibiuk, Baltimore, MD Devon Stuart, Harrisburg, PA

Dendrite function in neuron