Cutaneous Mechanoreceptors Flashcards
general moods of action
cutaneous mechanoreceptors
unencapsulated
no complex structure
commonly found on the skin
- penetrates dermis
- end in statrum
- surround hair follicles
range from slowly to rapid adapting
*are polymodal: detect temp. touch, pressure, stretch and cell damage
Free Nerve Ending
oval shaped
light on skin’s surface
abundant: finger tips and statum basal
Most sensitive of the tactile receptor for detecting fine touch & texture.
- provide steady- state signals, detecting continuous touch of objects against the skin
- slow adapting
Merkel Cells
encapsulated nerve ending
light&vibrations between 10 to 50 Hz
surrounded by horizontal lamellae of cells and connective tissue capsule
concentrated lips and finger tips
found within dermal papillae in glabrous (non-hairy) areas of skin
Meissner’s Corpuscles
spindle-shaped
free nerve endings intertwined w/ collagen fibers encased within a capsule
*sensitive to skin stretch and import. for grasping and holding objects
Highest density around fingernails, also found deep dermis where they signal the degree of joint rotation
respond to sustained pressure (little adaptation)
Ruffini Corpuscles
small round of oval-shaped encapsulated mechanoreceptors
found in dermis of dry skin as well as mucus membrane
-detect pressure & cold temperatures
Krause’s Corpuscles
Found in hairless skin (deep part of the dermis and fascia)
Nerve ending situated within a series of concentric layers of collage fibers& surrounding cells; encloused by a capsule
- respond to deep pressure &vibrations
- vary rapid adapting
Pacinian Corpuscles
What receptor detect sensation of cold and heat?
Thermoreceptors
open at dif. temp. and releases Ca2+ to detect temp. change in human
Transient receptor potential cation (TRP)
Do not open channels above 34C
TRPA 1
TRPM 8
concentrated in areas prone to injury
absent from brain and sparse on most internal organs
adapt very slowly- or non adapting
respond ro cellular damage, noxious chemical and signals released by the body itself
Nociception (pain)
0.1 sec. sharp or short pain, can be localized
fast pain
begins after one second, cannot be easily localized
slow pain
sudden onset but declines when the stimulus is removed
acute pain
persists; depends on the source as well
chronic pain
originating from abdominal organs, poorly localized
*reffered as “Pain”
visceral
Fibers with the slowest conduction velocity to the CNS
C fibers
Modify perception of pain
analgesics
reversibly block action potential generation in primary afferent fibers (block voltage-gated Na+ channels
anesthetics
chemicals produced by the body that module pain
endogenous opioids
inhibit pain transmission at central synapses
synthetic opioids
effective for symptoms of neuropathic pain
anticonvulsants
stronger stimuli activate more sensory units
recruitment
subsets of receptors respond to distinct ranges of stimuli
Range Fractionation
