Flashcards in Somatosensory Processing Deck (102):
Deformation of the DRG (free or encapsulated) by a mechanical stimulus _____ the threshold needed to evoke an action potential.
High-threshold channels characterize _____ (receptorss for pain).
Nociceptors are found predominantly in _____ _____.
Nociceptors are activated by _____ pressures.
Give information about the position of limbs and body in space.
Goldgi tendon organs
Stretching a mucle activates _____ on two types of afferent fibers:
Group 1a afferent fibers
large myelinated fibers
Group 2 afferent fibers
Tension of intrafusal fibers is also controlled by _____.
gamma motor neurons
(from dorsal horn spinal cord)
Large muscles for coarse movements have _____ spindles.
Extraocular muscles and uscles in the neck and hand have ____ spindles.
(require precise control)
Muscle spindles detect changes in _____.
Tactile afferents from body:
Dorsal column - medial lemniscal system
Afferents from face use the _____ (_____).
Merkel receptors have _____ responses.
Meissner receptors are _____.
Pacinian receptors are _____.
Ruffini receptors have _____ responses.
Merkel receptors are responsible for _____ and _____ perception.
Meissner receptors are responsible for _____ and _____.
Pacinian receptors are responsible for _____ perception and _____.
Ruffini receptors are responsible for _____, _____, and _____.
Slowly adapting afferents convey information about _____, such as size and shape.
Rapidly adapting afferents convey information about ______: dynamic qualities of the stimulus.
changes in ongoing stimulation
Sensory axons are classified according to their _____, which governs their _____ and their _____.
Cutaneous innervation related to a single spinal nerve
5 primary tasks of sensory systems
5 qualities of information to encode
5 factors that influence success or failure
Dorsal root ganglia
contain the sensory neurons of the somatosensory system
Dorsal root is responsible for _____.
Ventral root is responsible for _____.
The _____ system is responsible for touch perception.
dorsal column-medial lemniscus system
The _____ is responsible for pain perception.
The _____ projects to the cerebellum and controls timing of muscle contractions.
dorsal spinocerebellar tract
Proprioceptive afferents from the body lead to the _____ and _____.
dorsal column nuclei
The _____ somatosensory thalamus contains _____ afferents from the body.
central posterior lateral
The _____ somatosensory thalamus contains _____ afferents from the face.
ventral posterior medial
the somatosensory cortex contains _____ __, __, _, and _.
The _____ is a representation of the human body from the _____.
_____ serves as obligatory first step in cortical processing of somatosensory information.
Brodmann's area 3b
_____ are functioal modules of the cortex.
Columns in the somatosensory cortex are _____.
Reorganization of cortical maps in response to altered functional input is known as _____.
The neural encoding and processing of noxious stimuli
stimuli that can elicit tissue damage and activate nociceptors
Nociceptors are sensory receptors that detect signals from _____ and respond to _____ released.
Nociceptors are _____ found in the skin, muscle, joints, bone, and viscera.
free (bare) nerve endings
Pain processing is _____ of normal cuteaneous processing.
Peripheral axons responsible for normal stimulation _____ their frequency in response to painful stimuli.
do not increase
Nociceptive afferents only fire when _____.
stimuli reach high intensities
Direct stimulation of large fibers (1a, II, AB) _____.
does not produce pain
Peripheral nociceptive axons terminate in "_____."
Nociceptors are found on _____ fibers (_, _)
C fibers are _____ and respond to _____, _____, and _____ stimuli.
_____ fibers lack myelination.
Type I Ad fibers respond to dangerous _____ and _____ stimulation.
Type II Ad fibers respond to _____ stimulation.
_____ respond only to intense mechanical stimulation such as pinching, cutting, or stretching.
High threshold mechano-nociceptors
_____ respond to intense mechanical stimulation as well as to thermal stimulation.
_____ respond only to chemical substances.
_____ respond to all high intensity stimuli.
_____ include high-threshold mechanoreceptors, polymodal nociceptors, and ''silent'' nociceptors.
_____ include mechanoreceptors, thermal, silent and chemical nociceptors.
C and Ad fiber nerve endings contain _____ that respond to temp, pressure, and inflammatory agents.
transient receptor potential (TRP) channels
TRPV1 is activated by _____, _____, _____, and _____.
Transient receptor potential vanilloid type-1
TRPV1 channels are also known as _____ and _____.
vanilloid receptor 1
_____ are produced peripherally in response to injury.
acid-sensing ion channel
Increased sensitivity to painful stimuli
Hyperalgesia has a _____ effect at the level of the nociceptors.
Tissue damage and inflammation release inflammatory mediators, such as _____, _____, and _____ which increase the sensitivity of nociceptors to _____.
Most sensitizing pro-inflammatory agents activate the _____ pathway.
Phospolipace C pathway phosphorylates TRPV1, leading to _____.
sensitization of TRPV1
Pain sensation in response to non-painful stimuli
Allodynia results from an increase in excitability of _____.
dorsal horn neurons
The _____ localizes painful or thermal stimuli and leads to the _____.
spinothalamic tract (lateral and anterior)
thalamus (central lateral nucleus)
The _____ causes alertness and arousal in response to painful stimuli and leads to the _____.
reticular formation (through ret.form. of medulla and pons)
The _____ orients the eyes and head towards the stimuli and leads to the _____.
tectum (through periaqueductal gray matter)
The dorsal root ganglia pathway goes through _____.
Crossing of the anterolateral tract from left to right spinal cord occurs at the _____.
Visceral pain misperceived as somatic pain is called _____.
Non-nociceptive fibers of the anterolateral tract terminate in _____.
Unilateral spinal cord lesions lead to "dissociated sensory loss":
reduction in pain/temp sensation
reduction in touch/pressure/vibration/proprioception
The anterolateral system from the body runs through the _____ and the _____.
Ventral posterior lateral nucleos of the thalamus
The anterolateral system from the face runs through the _____ and the _____.
Ventral posterior medial nucleus of the thalamus
Sensory discriminative aspects of pain
Affective motivation aspects
The anterolateral system is divided into _____ and _____.
The sensory-discriminative anterolateral system leads to the _____.
Stimulation of the periaqueductal gray in the midbrain is _____.
_____ in the spinal cord modulate pain perception.
Nociceptive information is modulated by simultaneous activity in _____.
Peptide that binds to the same posynaptic receptors as opium
_____ is the active ingredient in the sap/seeds of opium poppies.
Morphine, heroin, and synthetic opiates such as methadone and fentanyl are potent _____.
3 groups of endogenous opioid receptor ligands:
_____ modulate transmission of ascending pain signals.