Dendrites are treelike extensions at the beginning of a neuron that help increase the surface area of the cell body. These tiny protrusions receive information from other neurons and transmit electrical stimulation to the soma. Dendrites are also covered with synapses.
Characteristics of Dendrite:
* Most neurons have many dendrites
* However, some neurons may have only one dendrite
* Short and highly branched
* Transmits information to the cell body
The largest of the membrane-bound organelles, the nucleus first was described in 1710 by Antoni van Leeuwenhoek using a simple microscope. In 1831 the Scottish botanist Robert Brown characterized the organelle in detail, calling it the "nucleus", from the Latin word for "little nut." The nucleus is the site of gene expression and gene regulation.
The axon is the main conducting unit of the neuron, capable of conveying electrical signals along distances that range from as short as 0.1 mm to as long as 2 m. Many axon split into several branches, thereby conveying information to different targets. Many neurons do not have axons. In these socalled amacrine neurons, all the neuronal processes are dendrites. Neurons with very short axons are also found.
The axons of many neurons are wrapped in a myelin sheat, which is composed of the membranes of intersticial cells and is wrapped around the axons to form several concentric layers. The myelin sheath is broken at various points by the nodes of Ranvier, so that in cross section it looks like a string of sausages. The myelin protects the axon, and prevents interference between axons as they pass along in bundles, sometimes thousands at time.