PSL440Y1 Chapter 10, 13: PSL440 Textbook Notes
Document Summary
Nociceptors unspecialized nerve cell endings that initiate sensation of pain. Adelta group axons myelinated (fast), c fiber group axons unmyelinated (slow) Two categories of pain perception: sharp first pain (from adelta fibers, delayed, longer-lasting second pain (from c fibers) Adelta fibers: specialized pathways for transmission of heat and mechanical stimuli. C fibers: respond to all thermal, mechanical, and chemical nociceptive stimuli (ie. polymodal, though have subsets that respond preferentially to heat or chemical stimulation. Is part of the family of transient receptor potential (trp) channels. Under resting conditions the pore of these channels are closed. In open state, there"s influx of na and ca that initiates aps in nociceptive fibers. Voltage-gated na and k channels are important part of conveying aps from nociceptive fibers to the dorsal horn of spinal cord: na channel nav1. 7 is especially important for transmission of nociceptive information. Non-nociceptive afferents terminate primarily in lamina 5.
