Neuron (image) University of California - Santa Barbara Share Print E-Mail Caption Shown is an illustration of a neuron, which is the basic functional unit of the nervous system. Enlarged portion indicates myelin sheath which is a multilamellar membrane surrounding the axon of neurons. Credit Dottie McLaren Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.