Aδ, or A-delta fibers, are a type of nerve fiber found in the peripheral nervous system. They are responsible for transmitting sharp, acute pain sensations and temperature changes. Aδ fibers are myelinated, which means they have a protective sheath that allows for faster signal transmission compared to unmyelinated fibers. These fibers play a crucial role in the body's response to injury and environmental stimuli. When activated, Aδ fibers send signals to the brain, prompting a quick reaction, such as withdrawing from a painful stimulus. This rapid response is essential for protecting the body from harm and is part of the overall pain pathway involving nociceptors and the central nervous system.