sensory system Flashcards
location of 1st order sensory neurons innervating the body
dorsal root ganglia
location of 1st order sensory neurons innervating the head
trigeminal ganglion
afferent (sensory) fibers
encapsulated & free nerve endings
encapsulated
by specialized receptor cells
mechanoreceptors: tactile & proprioceptive
free nerve endings
lack specialized receptor cells
pain, temp, itch, etc.
skin mechanoreceptors
tactile information
4 classes
-encapsulated
proprioception mechanoreceptors
the ability to sense the position and location and orientation and movement of the body and its parts
-encapsulated
free nerve endings
Adelta & C fibers
pain, temp, itch, ache/burn, sensual touch
Adelta
SHARP 1ST PAIN lightly myelinated faster conducting thermal stimuli intense mechanical stimuli TRPV1 & TRPV2
C
BURNING 2ND PAIN unmyelinated slow conducting thermal stimuli intense mechanical stimuli chemical stimuli (polymodal) TRPV1
merkel cells
stimulus?
role?
25% of hand only type in epidermis small receptive field stimulus: edges/corners role: perception of form & texture
meissner’s corpuscles
stimulus?
role?
40% of hand in dermal papillae close to skin surface stimulus: skin motion, low-frequency vibration when objects move across skin role: slippage detection
pacinian corpuscles
stimulus?
role?
10-15% in hand deep in dermis large receptive field stimulus: vibration role: perception of distant events (transmitted vibration), use of tools
ruffini’s endings
stimulus?
role?
20% in hand
deep in dermis
large receptive field
stimulus: stretch of skin by finger or limb movement
role: detection of hand shape and finger motion
(works together w/ proprioceptors)
stereognosis
the ability to recognize the form and nature of an object using only the sense of touch
