How do we sense different types of pain? Using what you understand about threshold potentials and al

Pain is caused by extreme pressure, temperature and chemicals - all of which have the possibility to damage tissues. Nociceptors (pain receptors) (note that these receptors can also be classified as thermoreceptors, chemoreceptors etc.)  will detect these stimuli and send the appropriate nerve impulse to the the central nervous system for integration. As action potentials are an 'all or nothing' even the central nervous system will interpret the intensity of the pain by the number of receptors transmitting the signal as well as the frequency at which these impulses are relayed.

Pain perception can also be enhanced by the body - for example the body may produced prostaglandins when a tissue is damaged to trigger the nociceptors; preventing further damage