What defines a neuron?

A neuron is defined as the fundamental unit of the nervous system that conducts signals. Neurons are specialized cells designed to transmit information throughout the body via electrical and chemical signals. They play a critical role in receiving stimuli, processing information, and sending signals to other neurons, muscles, or glands. This unique ability allows neurons to facilitate communication within the nervous system, making them essential for all nervous system functions, including reflexes, sensory perception, and motor control.

The other choices describe different types of cells or functions within the body. Muscle cells indeed have a different role, which is to enable movement through contraction, while connective tissue cells provide structural support rather than signal conduction. The part of the brain responsible for memory refers specifically to regions involved in storing and retrieving information, which is a specific functional role rather than a definition of what a neuron is. Thus, the definition of a neuron stands out as focusing on its role in signal conduction and its foundational status in the nervous system.