Neuron

A neuron is a nerve cell - the basic functional unit of the nervous system specialized to receive and transmit signals. Neurons typically have a cell body, dendrites (branches that receive inputs), and an axon (a long fiber that sends impulses to other cells). These cells communicate via electrical impulses and chemical neurotransmitters, allowing rapid messaging throughout the body.

• Neurons have unique structures: dendrites (collect incoming signals), a cell body (with nucleus), and usually one axon (carries outgoing nerve impulse). Many axons are insulated with myelin to speed up signal conduction.
• Neurons do not usually undergo cell division (they are generally non-mitotic), which is why nerve damage can be long-lasting. Some parts of the brain can grow new neurons (neurogenesis), but this is limited.
• There are different types of neurons by function: sensory neurons (bring information from body to brain/spinal cord), motor neurons (carry signals to muscles/glands), and interneurons (connect neurons within the central nervous system).

• If a question asks for the "basic unit of the nervous system" or the cell type that transmits nerve impulses, the answer is the neuron.
• Be careful not to confuse a neuron with a nerve. A nerve is a bundle of many neuron axons in the peripheral nervous system, whereas a neuron is a single cell. For example, a question might ask about an impulse traveling down a nerve fiber - that fiber is part of a neuron's axon.
• Neurons vs glial cells: exams may test that neurons conduct impulses, while glial cells (neuroglia) are supporting cells. For instance, an item might describe a cell that insulates axons (like a Schwann cell or oligodendrocyte) - that is a glial cell, not a neuron.