Types and Functions of Neurons

Types of Neurons

• Multipolar Neurons:

  • Feature many processes including multiple dendrites and a single axon.
  • Constitute the majority of neurons in the Central Nervous System (CNS).
  • Examples include motor neurons and interneurons.

• Bipolar Neurons:

  • Characterized by two processes: one dendrite and one axon on opposite sides of the cell body.
  • Found in special sensory areas, including the retina of the eye, olfactory (nose) cells, and inner ear.

• Unipolar Neurons:

  • Have only one process, which serves as an axon that connects to the neuron cell body.
  • Small dendrites branch off the axon rather than directly attaching to the cell body.
  • Function primarily as sensory neurons, transporting sensory data from skin, muscles, and organs to the spinal cord.

Functions of Neurons

• Functional Classifications:

  • Neurons can be classified based on their function into three categories: sensory neurons, interneurons (association neurons), and motor neurons.

• Sensory (Afferent) Neurons:

  • Detect environmental changes through stimuli using receptors associated with dendrites.
  • Convert stimuli into action potentials that travel along the axon to the spinal cord.
  • Structurally unipolar and located in the spinal cord; their axons synapse with motor neurons or interneurons.

• Interneurons:

  • Structurally classified as multipolar neurons.
  • Comprise approximately 90% of the neurons in the CNS.
  • Facilitate communication in the spinal cord by either connecting with a series of interneurons leading to the brain or synapsing with motor neurons.

• Motor (Efferent) Neurons:

  • Responsible for transmitting impulses away from the spinal cord to effectors, such as muscles or glands.
  • Typically classified as multipolar neurons.