Week 2-Pain & Opioids Flashcards
What is the definition of pain?
Physical, emotional, and psychological condition that does not necessarily correlate to the degree of tissue damage present.
What are components of the phenomenon known as pain?
Sensory-discriminative & Motivational-affective
Define sensory-discriminative.
component of pain depends on ascending projections of tracts (including the spinothalamic and trigeminothalamic tracts) to the cerebral cortex. Sensory processing at these higher levels results in the perception of the quality of pain (pricking, burning, aching), the location of the painful stimulus, and the intensity of the pain.
Define motivational-affective.
responses to painful stimuli include attention and arousal, somatic and autonomic reflexes, endocrine responses, and emotional changes
What effect does pain have on society?
Great cost to society in treatment and loss of production
What are nociceptors?
Pain receptors, Specialized class of primary afferents that respond to intense, noxious stimuli in skin, muscles, joints, viscera, and vasculature.
What stimuli do nociceptors respond to?
Respond to thermal, mechanical, and chemical stimuli
What information do nociceptors provide to the CNS?
location and intensity of the stimuli
Nociceptors are generally ________________
Generally inactive until stimulated by enough energy to reach the stimulus threshold
What are the four components of nociception (The experience of pain involves a series of complex neurophysiologic processes)?
transduction, transmission, modulation, and perception.
Nociception is the ________system’s response to certain harmful or potentially harmful stimuli
sensory nervous system
Define transduction.
Process by which noxious stimuli (heat, cold, mechanical distortion) are converted to nerve electrical impulses in sensory nerve endings
Define transmission.
Conduction of those impulses to the CNS (dorsal horn of the spinal cord and thalamus which has projections to cingulate, insular, somatosensory cortices)
Define modulation.
Process of altering pain transmission–CNS/PNS inhibitory & excitatory mechanisms
Define perception.
Mediated through the thalamus acting as the central relay station for incoming pain signals and the primary somatosensory complex which serves to discriminate specific sensory experiences
Does the occurrence of pain depend on all four steps of nociceptive process? What is an example of when this wouldn’t occur?
No
For example, pain from trigeminal neuralgia occurs in the absence of transduction of a chemical stimulus at a nociceptor reflecting axonal discharges initiated at the site of a compressed or demyelinated nerve. Modulation of pain impulses may not occur if specific nervous system tracts are injured. For example, phantom limb pain occurs in the absence of nociception or nociceptors (pain receptors).
Specific types of nociceptors react to ________.
different stimuli
What is the reaction of the alpha delta peripheral nerve fibers?
Fast pain (sharp pain)
Is the alpha delta peripheral nerve fibers myelinated or unmyelinated?
Myelinated
What is the fiber diameter of the alpha delta peripheral nerve fibers?
2-5 mm
What is the reaction of the C peripheral nerve fibers?
Slow pain (+cold, throbbing, burning)
Is the C peripheral nerve fibers myelinated or unmyelinated?
Unmyelinated
What is the fiber diameter of the C peripheral nerve fibers?
0.4-1.2
Cell damage results in disruption of phospholipid membrane causes the release of _______________ to became various eicosanoids which include prostaglandins
arachidonic acid that is acted upon by intracellular COX enzymes (cyclo-oxygenase)