Structure of Neurons: Basics You Need to Know
Basic Component of a Neuron
The size and shape of a typical neuron is distinctly different than any other cell in the human body. The diameter of a neuron is between 5 and 150 µm.
Like most of the cells in the body, neurons also consist of a cell body. The cell body is the core component of a nerve cell. It contains nucleus, cytoplasm and other organelles. The cell body that contain a euchromatic nucleus often has a prominent nucleolus. This nucleolus contains finely dispersed chromatin.
The cytoplasm of the cell body is composed of nissl bodies, golgi complex, neurofibrils, mitochondria, lysosomes and centriole. Unlike most of the cells, neurons also consist of two major parts, an axon and multiple dendrites.
Learn more about Neurons
Diagram of a basic neuron and its components
Typically, each neuron has multiple dendrites. They usually arise from the cell body and appear as the branches of a tree. Dendrites also contain cytoplasm. The composition of the dendrite cytoplasm is quite similar to the cell body. However, nucleus and golgi complex are absent in the dendrite cytoplasm.
Usually, neurons have only one axon. This is a branched process with a single, long or tail like structure. Like dendrites, this single structure also arises from the cell body. Usually, axon arises at the axon hillock, a short pyramid shaped region, of the cell body and terminates in twig-like branching called telodendria.
Most axons are covered by a sheath of lipoprotein complex, called myelin sheath. The bulbous enlargement or the end of axon terminal called as terminal buttons.
Structure of multipolar neuron
Image source:
- BruceBlaus, CC BY 3.0, via Wikimedia Commons
- Jennifer Walinga, CC BY-SA 4.0, via Wikimedia Commons
