Neuro: Viscerosomatic Sensation Flashcards
(24 cards)
In the somatic sensory system, neurons of the ____ act as sensory receptors, and are the first order neurons in the somatosensory pathway.
DRG
“_____ _____” sharpens contrast between stimuli across receptive fields, ensuring that the strongest of two or more competing signals is expressed in the cortex.
surround inhibition
A ______ _____ is the region of space in which the presence of a stimulus will alter the firing of a particular neuron.
receptive field
______ nociceptors are activated by intensive pressure applied to the skin using fast-conducting Αδ fibers.
Mechanical
____-_____ receptors continue to produce action potentials over the duration of a stimulus and signal magnitude/intensity of a signal.
slow-adapting
_____ nociceptors are found in joint capsules and ligaments, but not cartilage.
Joint
What are the two types of mechanoreceptors in the superficial layer of the skin, and what sensations do they detect?
Meissner’s corpuscles - stroking/fluttering sensations Merkel’s disks - pressure
Most _______ nociceptors are believed to be chemoreceptors sensitive to substances in the tissue produced by inflammation or ischemia
visceral
Upon repeated application of noxious mechanical stimuli, previously unresponsive nociceptors become responsive. This is illustrative of what process?
peripheral sensitization
Fast-conducting, fast-adapting fibers that respond to changes in muscle length, excite alpha motor neurons during deep tendon reflex and increase muscle tension.
Type 1a fibers
Higher centers involved in the perception of pain incorrectly ascribing pain stimuli to the skin instead of the deeper visceral structure is a concept known as what?
Referred pain
_____ nociceptors are located in connective tissue surrounding muscle fibers; activation results in poorly localized aching/cramping.
Muscle
Condition whereby: • ↓ response threshold to noxious stimuli • ↑ response magnitude to noxious stimuli • ↑ response to innocuous stimuli • spontaneous pain experienced • large ↑ in receptive field size of central neurons
secondary hyperalgesia
This special class of nociceptor does not respond at all to thermal, mechanical, or chemical stimuli unless injury has occurred, and their firing threshold is reduced by inflammation and chemical insults.
Silent nociceptors
Fast-conducting fibers that respond to tendon stretch/muscle contraction, inhibiting alpha motor neurons and increasing muscle relaxation
Type 1b fibers
____-_____ receptors diminish in response to stimuli very quickly and then stop firing until there is a change in stimulus intensity. They signal rate or velocity of a signal.
Fast-adapting
______ nociceptors are activated by extreme temperatures (< 5°C or > 45°C) using fast-conducting Αδ fibers.
Thermal
Condition whereby: • ↓ response threshold to noxious stimuli • ↑ response magnitude to noxious stimuli • spontaneous activation of nociceptors • small ↑ in receptive field size of nociceptors
primary hyperalgesia
Fast-adapting receptors
Pacinian and Meissner’s corpuscles
Slow-adapting receptors
Merkel’s disks and Ruffini endings
What are the two types of mechanoreceptors in the deep subcutaneous tissue, and what sensations do they detect?
Pacinian corpuscles - vibration Ruffini endings - skin stretch
All cutaneous mechanoreceptors use fast-conducting ____ fibers.
Aβ
_____ nociceptors are activated by high-intensity chemical, mechanical, or thermal stimuli, using non-myelinated, slow-adapting C fibers
Polymodal
A majority of visceral afferents are ____ and ___ fibers.
Aδ and C
