• Though varying greatly in size and shape, neurons have three principal regions
  1. a cell body: contains the nucleus and is the place where macromolecules are produced
  2. dendrites: thin branched processes that extend from the cytoplasm of the cell body. Serve as receptive elements that transmit electrica impluses to the cell body
  3. an axon: is the longer process; transmits signals away from the cell body.
  • Neurons form connections with one another through Synapses.
Classification of Neurons
  • Two ways to classify neurons: Functional or Structural.
  • The Functional Classification is divided into three parts:
  i. Sensory (Afferent) Neurons conduct impulses from the sensory receptors to the central nervous system.
  ii. Motor (Efferent) Neurons conduct impluses from the CNS to the muscles and glands.
  iii. Association Neurons (Interneurons) located entirely within the CNS and have integrattive or associative functions.
  • The Structural Classification is based on the number of processes that extend from the cell body
  i. Bipolar Neurons have two processes, one at either end.
  ii. Multipolar Neurons have several dendrites and one axon extending from the cell body; most numerous of the neurons
  iii. Pseudounipolar Neurons have a single process that divides like a T to form a longer process.