The Nervous System, Somatic Sensations, Pain, Headache and Thermal Sensations
Pain Sensation: fast and Slow Pain Classification Fast Pain Slow Pain All pain receptors are free nerve endings Three types of Stimuli Pain receptors are activated by mechanical, thermal and chemical stimuli Mechanical and thermal stimuli - fast pain Chemical stimuli - slow pain No adaptation, progressively greater as the pain stimulus continues, this is called hyperalgesia Two separate pathways of Pain transmission A-delta fibers fast - 6 to 30m/s - Mechanical and thermal stimuli C-Fibers slow - 0.5 to 2m/s neospinothalamic tract - A-delta fibers paleospinothalamic tract - C-fibers The neospinothalamic tract is used in pain localisation Activity in the paleospinothalamic system may impart unpleasant perception of pain. paleospinothalamic pathway Brain and Spinal Cord: Internal Pain Suppression system The periaqueductal gray the periadueductal gray of the midbrain and the rostral pons receives input from the ascending pain pathways in addition to...