In spite of its subjective nature, most pain is associated with tissue damage and has a physiological basis. Not all tissues, however, are sensitive to the same type of injury. For example, although skin is sensitive to burning and cutting, the visceral organs can be cut without generating pain. Overdistension or chemical irritation of the visceral surface, however, will induce pain. Some tissues do not give rise to pain, no matter how they are stimulated; the liver and the alveoli of the lungs are insensitive to almost every stimulus. Thus, tissues respond only to the specific stimuli that they are ...(100 of 3220 words)