Psych 365- ch 11 (pain: the significance of pain, pain serves at least 3 functions: First the pain that occurs before serious injury (ie touch something hot) prevents further injury. Second prevent further injury serving as basis of learning. When activated these generate impulses that travel to cns. Afferent peripheral fibres that transmit pain impulses are a-delta fibres (sharp distinct pain) and c-fibres (dull/diffuse/aching pain: a-delta fibres small, myelinated that transmit impulses very quickly, c fibres transmit slower b/c not myelinated. Intense involvement in other activities, relaxation or positive experiences can mute pain by closing gate. Gate control theory can"t explain phantom limb pain: experience of pain in absent body part. Slow of block transmission of nerve impulses. Temporary, physiological responses partly proportional to stimulus intensity, can cause considerable anxiety: chronic pain: lasting longer than 6 months- nearly 1/3 of canadians. Can be intermittent or constant, mild or severe, varies greatly.