Physiology: Animal Function and Reproduction

Nervous System

What are neurons, nerve dendrites, and axons?

Neurons are specialized cells that produce and conduct “impulses,” or nerve signals. Neurons consist of a cell body containing a nucleus and two types of cytoplasmic extensions, dendrites and axons. Dendrites are thin, highly branched extensions that receive signals. Axons are tubular extensions that transmit nerve impulses away from the cell body, often to another neuron. Other cells in nerve tissue nourish the neurons, insulate the dendrites and axons, and promote quicker transmission of signals. (For more about cells, see the chapter “Cellular Basics.”)


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