Pain receptors, also known as nociceptors, are specialized nerve endings that detect harmful stimuli, such as extreme heat, pressure, or chemical changes. They are found throughout the body, including the skin, muscles, and internal organs. When activated, these receptors send signals to the brain, which interprets them as pain. There are different types of pain receptors, including A-delta fibers that transmit sharp, quick pain and C fibers that carry dull, aching sensations. This dual system helps the body respond appropriately to potential injuries, prompting protective actions like withdrawing from harmful situations.