Neurons are the cells that transmit electrical impulses around the brain and the other parts of the central nervous system.

  • Neurons are the electrically excitable cells that are the fundamental building blocks of the central nervous system of human beings.
  • Neurons interconnect the systems and organs that maintain the body’s essential functions.
  • Neurons send and receive signals that allow us to sense the external world, move, think, form memories and much more.
  • Neurons are of three principal types: motor neurons, sensory neurons and interneurons.
  • Neurons connect together via specialized filaments called synapses.
  • In the neocortex (making up about 80% of the human brain), approximately 70-80% of nervous tissue is in the form of neurons whilst the remainder is composed of interneurons.
About the anatomy of neurons
  • A typical neuron consists of a cell body (soma), dendrites, and a single axon.
  • Dendrites and axons form filament-like extensions of the soma.
  • Dendrites typically form into a profusion of branches as they extend from the soma.
  • An axon can be as long as a metre in length.
  • At the farthest tip of the axon’s branches are axon terminals, where the neuron can transmit a signal across a synapse to another cell.
About interneurons
  • Interneurons are also referred to as relay neurons, connector neurons, intermediate neurons and local circuit neurons each of which helps to explain their function.
  • Interneurons form nodes within neural circuits, enabling communication between sensory or motor neurons and the central nervous system.
  • Interneurons can be further broken down into two groups: local interneurons and relay interneurons.
    • Local interneurons have short axons and form circuits with nearby neurons to analyse small pieces of information.
    • Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions.
  • The interaction between interneurons allows the brain to perform complex functions such as sense-making.
About neurons and the human retina