Slide 5 of 9
Notes:
Glabrous skin has high cutaneous sensitivity; I.e. our skin without hair (like fingers, face) is very sensitive to touch (Demo of this..try tickling a baby’s feet).
Touch—AP in somatosensory system (touch) thought to be bending of tip of Pacinian corpuscle b/c this opens the ion channels? AP {similar to the tension & bending necessary to create AP in audition}
Adaptation: Moderate & constant stimulus will not produce sensation after it is present for a period of time. Lack of sensation due to absence of receptor firing. E.g. After a while we don’t perceive the clothes on our bodies, or the watch or glasses we commonly wear; we adapt to these stimuli.
Stimuli & Motor info: Somatosenses work with the motor system to help us get the info we need about the objects we come into contact with (Demo, try blindfolding a willing friend and ask him/her to identify common objects just by touch).
Temperature: 2 thermal receptors—cool (surface) & warm (deeper in skin). Thermosensation uses free nerve endings. AP here may be due to Na+-K+ pump
Pain: Naloxone is opiate receptor blocker
