Lecture 45 - somatosensory 1 Flashcards
what are the conscious sensory systems
- olfactory
- gustatory
- somatosensory
- visual
- auditory
what are the unconscious sensory systems
- vestibular
- proprioceptive
- vomeronasal
- circadian
what are the 3 transduction receptors
- chemoreceptor
- mechanoreceptor
- photoreceptor
what cation is excitatory for chemoreceptors? what anion?
Na+, Cl-
what are the 4 primary somatic sensations
- tactile
- position (proprioceptive)
- pain
- temperature
what tactile sensation is in:
free nerve endings
respond to mechanical, thermal, and noxious stimuli
what tactile sensation is in:
merkels discs
response to 5-15 Hz
what tactile sensation is in:
meissner’s corpuscles
response to 20-40 Hz
what tactile sensation is in:
pacinian corpuscles
deep pain
respond to 150-300 Hz
what tactile sensation is in:
Hair follicle endings
respond to hair displacement
what tactile sensation is in:
Krause’s corpuscle
in lips, tongue, and genitals
respond to pressure
what tactile sensation is in:
ruffini’s end-organ
respond to pressure
describe the anatomy of the Pacinian corpuscle
axon with unmyelinated tip encapsulated by concentric layers of connective tissue
summarize the mechanism of Pacinian corpuscle stimulation
- pressure deforms capsule
- fluid compressed and deforms nerve membrane
- mechanically gated Na+ channels in nerve terminal open
- local depolarization occur
- action potential generated
what properties cause adaptation in Pacinian corpuscles
- capsule is viscoelastic (reduces force)
- slow recovery of ion gradients after multiple action potentials
- receptor desensitization
