Pain receptors, also known as nociceptors, are specialized nerve endings that detect harmful stimuli, such as extreme temperatures, pressure, or chemical changes. They play a crucial role in the body's defense system by alerting us to potential injuries or threats. When activated, these receptors send signals to the brain, which interprets them as pain. There are different types of pain receptors, including thermal, mechanical, and chemical nociceptors, each responding to specific types of harmful stimuli. The activation of these receptors helps initiate protective reflexes, such as withdrawing from a painful stimulus, and promotes healing by encouraging individuals to avoid further injury.