Three main categories of nociceptors:
- Mechanical – Mechanical pressure is perhaps the most common cause of pain. If you roll your ankle, your ligaments are being stretched too far, which can set off mechanical nociceptors.
- Temperature – Extreme temperatures are another common cause of pain – if you touch something very hot, you’ll set off temperature nociceptors, which may signal pain even before you get burned!
- Chemical – Chemicals can activate nociceptors too. For example, when you have an injury or infection, the affected area becomes inflamed. Inflammation is an important first step in your body’s healing process – it brings blood and important chemicals to the damaged area to aid in the the repair process. Some of these inflammatory chemicals also affect pain in a couple of ways. Chemical might activate nociceptors to produce pain (sometimes constantly), and some chemicals can lower the threshold of activation in other nociceptors, making you more sensitive to pain in general!