A delta fiber, also known as a A-delta fiber or Aδ fiber, is a type of nerve fiber found in the peripheral nervous system of vertebrates, including humans. These fibers are part of the somatosensory system and play a crucial role in transmitting sensory information, particularly pain signals, from different parts of the body to the brain.
A delta fibers are classified as small-diameter, myelinated nerve fibers, meaning they possess a myelin sheath that covers the axon, the long projection of the nerve cell. This myelin sheath serves as insulation, which enables the nerve impulses to travel faster along the fiber.
These fibers are involved in transmitting fast, sharp, and localized pain sensations, often referred to as "first pain." When an injury or noxious stimulus occurs, such as a cut or a burn, the A-delta fibers activate and rapidly send signals to the spinal cord and then onto the brain, providing an initial perception of pain.
Compared to another type of nerve fiber called C fibers, A delta fibers have a larger diameter and conduct nerve impulses at a faster speed. This faster conduction velocity allows individuals to react quickly to potentially harmful stimuli and take appropriate action to avoid further injury.
In summary, A delta fibers are small-diameter, myelinated nerve fibers in the somatosensory system that rapidly transmit sharp and localized pain signals to the brain. These fibers play a crucial role in the initial perception of pain and facilitate a fast response to harmful stimuli.
