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Mechanoreceptors use which type of fibers?
A-beta
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Termal receptors use which type of fibers?
- Heat - C-fibers
- Cold - A-delta
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Proprioceptors in joints contain which type of fibers?
A-alpha - are fast for signaling of body position at tendons and muscles
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Nociceptors contain which type of fibers?
A delta and C fibers
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Cutaneus receptors include:
- Mechanoreceptors
- Thermal receptors
- Nociceptors
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Receptor types in joints/tendons/muscles
- Mechanoreceptors (A beta)- pressure receptors of stretch
- Proprioceptors (A alpha)
- Nociceptors (A delta and C) - excited by intense pressure stretching or chemicals
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Receptors in viscera:
- Mechanoreceptors - stretching or pressure on organs
- Nociceptors - deep, dull pain from viscera (A delta, C)
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Receptors in bone:
Nociceptors - dull, aching pain -- mostly C fibers (some A delta)
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Transduction in sensory receptors
- Adequate stimulus
- Change in membrane potential
- Transmission of action potential
- Adaptation
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Transduction in a mechanoreceptor:
- Displacement of hair
- Stretch sensitive channels on dendrite open
- Influx of Na+
- Voltage sensitive Na and K channels open
- Nerve impulse
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Adaptation of mechanoreceptors
- Slowly - proprioceptors
- Rapidly - hair receptors
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Phasic Receptor
Normally not active. Ex: Nociceptors
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Tonic Receptor
Always active. Ex: Proprioceptors
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Sensory afferents synapse and relese neurotransmitter at the _________
Dorsal horn (except pain fibers)
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Afferent pain fibers are ________
high in the dorsal horn
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Steriognosis is:
The perception of the size and shape of objects by touch
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First order neurons transmit from the _____ to the _____.
Periphery; Brainstem
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Second order neurons transmit from the ________ to the _______.
Brainstem to the thalamus
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Connective tissue is found in the ____ layer of skin:
Dermis
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The 2 types of encapsulated, layered skin receptors are:
- Pacinian corpuscles
- Meissner corpuscles
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A type of encapsulated, thin capsule of skin receptor is:
Ruffini endings
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Two types of accessory, nonencapsulated structures are:
- Endings around hairs
- Merkel endings
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The three types of skin receptors are:
- Encapsulated
- Nonencapsulated
- Free nerve endings
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Pacinian corpuscles are located in what types of skin?
Hairy and hairless
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Pacinian receptor endings are found in the:
Deep epidermis (layers of epithelial cells; ECF)
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Pacinian corpuscles are _____ adapting
Rapidly
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Function of Pacinian corpuscle is:
- To record vibration applied to surface of skin
- Texture discrimination
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Meissner corpuscles are located in _____ skin:
Hairless only in superficial dermis
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Receptor endings of Meissner corpuscles in:
Nestled in epithelial layer
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Meissner corpuscles are ______ adaptive
Rapidly
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Function of Meissner corpuscles is:
- Touch sense
- Vibration
- Texture discrimination
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Ruffini endings are found in ____ skin:
Hairy and hairless; dermis
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Receptor endings of Ruffini endings are:
Collagen wrapped around ending in dermis
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Ruffini endings are ______ adaptive:
Slowly
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Function of Ruffini endings is:
Detect skin stretching and pressure
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Dermatomes are:
cutaneus territories innervated by spinal nerves (cervical, thoracic, lumbar, sacral)
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