PNB 2274 Lecture Notes - Lecture 19: Transient Receptor Potential Channel, Periaqueductal Gray, Raphe Nuclei
12 Apr 2018
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Document Summary
Pain-an unpleasant sensory and emotional experience associated w/ damage. Nociceptors for pain, have free nerve endings, contain trp (transient receptor potential) channels that play role in pain. Includes polymodal (multiple types of damage), silent (only work when inflammation of tissue already, so silent in most cases), chemical, thermal (very hot or cold), and high-threshold mechano-nociceptors. These are sensitized by prolonged stimulation, ignoring it lowers the pain threshold. Factors that activate nociceptors are what damaged tissues release (see slide) Aspirin works by stopping ana acid (see slide) A-delta fibers are myelinated, small field but faster travel, and mainly mechanical specific, so gives a sharp/prickling sensation. C fibers much slower (. 5-2 m/s, earthworm was 15-20 at room temp) large receptor field means little discrimination, will give burning or aching. Combination of the 2 cause double pain sensation. Neospinothalamic tract is anterolateral, responsible for immediate awareness of exact location of painful stimulus (a-delta).
