A peripheral nerve that carries sensations, including nociceptive stimuli that result in acute pain; larger and faster-acting than C fibers.

A peripheral nerve that carries sensations, including nociceptive stimuli that result in acute pain; larger and faster-acting than C fibers.

• A. A-delta fiber
• B. A fiber
• C. C fiber
• D. B fiber

Answer: (A)

This describes the A-delta fiber. These fibers are thinly myelinated, which makes them faster conductors than the unmyelinated C fibers. They carry nociceptive input that produces acute, immediate, well-localized pain, so they respond quickly to harmful stimuli and alert you right away. Conduction velocities for A-delta fibers are higher than C fibers (roughly in the range of several meters per second up to a few dozen m/s), which explains the fast, sharp pain you notice. By contrast, C fibers are unmyelinated and convey slower, duller, lingering pain, and B fibers are autonomic and not primarily responsible for fast nociceptive signaling.

This describes the A-delta fiber. These fibers are thinly myelinated, which makes them faster conductors than the unmyelinated C fibers. They carry nociceptive input that produces acute, immediate, well-localized pain, so they respond quickly to harmful stimuli and alert you right away. Conduction velocities for A-delta fibers are higher than C fibers (roughly in the range of several meters per second up to a few dozen m/s), which explains the fast, sharp pain you notice. By contrast, C fibers are unmyelinated and convey slower, duller, lingering pain, and B fibers are autonomic and not primarily responsible for fast nociceptive signaling.