NSE 13A/B Chapter Notes - Chapter 11: Spinothalamic Tract, Substantia Gelatinosa Of Rolando, Noxious Stimulus
Document Summary
A fibers: myelinated; larger in diameter; transmit the pain signal rapidly to the. Cns; results in very localized, short-term, and sharp sensations. Nociception: how noxious stimuli are typically perceived as pain: transduction: occurs when a noxious stimulus in the form of traumatic or chemical injury, burn, incision, or tumor growth occurs in the periphery. Injured tissue release neurotransmitters (substance p, histamine, prostaglandins, serotonin, and bradykinin) to propagate an action potential along sensory nerve fibers to the spinal cord. The nerve fibers terminate in the dorsal horn, and a second set of neurotransmitters carries the pain impulse: transmission: the pain impulse moves from the level of the spinal cord to the brain. Opioid receptors in the spinal cord can block pain signaling with endogenous or exogenous opioids. If the opioid receptors are uninterrupted, the pain impulse moves to the brain via various ascending fibers in the spinothalamic tract that terminate in the brain stem and thalamus.
