Pain Flashcards
What are the two categories of pain?
Nociceptive pain and pathological pain.
What is nociceptive pain?
Pain triggered by a noxious stimuli, triggers withdrawal reflex. Important for survival.
What is pathological pain?
Pain caused by a neural lesion, abnormally processed due to neural damage, no longer important for survival.
What is allodynia?
Pain due to a stimulus which does normally not cause pain.
What is neuropathy?
Disturbance in function or pathological change in a nerve.
What is central pain?
Pain caused by a primary lesion or dysfunction in the nervous system.
What is dysesthesia?
Unpleasant abnormal sensation.
What is paresthesia?
Abnormal sensation, whether spontaneous or evokes.
What is hyperesthesia?
Increased sensitivity to stimulation.
What is hypoesthesia?
Decreased sensitivity to stimulation.
What is the gate control theory of pain?
Pain is modulated due to agtes within the spinal cord that can be open or closed; G-cell is a gate cell whereas T-cell is a transmission cell.
Who discovered the gate control theory of pain?
Wall and Melzack
What are the four segments of the spinal cord?
Cervical, thoracic, lumbar, sacral.
Where are primary sensory neurons located?
In the dorsal root ganglion.
What fibers are present in the DRG?
Large light and small dark.
What fibers make up the large light?
A-alpha and A-beta.
What fibers make up the small dark?
A-sigma and C.
What is the function of the large light?
Detect non-painful stimuli; touch and proprioception.
What is the function of small dark?
Painful sensation and temperature.
What to A-alpha and A-beta fibers detect?
Light touch and proprioception.
What do A-delta fibers detect?
Nociception.
What do C-fibers detect?
Itch, innocuous temperatures; make up the ‘second pain’.
Where do A-beta fibers project?
Deep lamina (III, IV, V)
Where do A-sigma fibers project?
Superficial and deep lamina (I, II, V)
Where do C nociceptors project?
Superficial layers.
Where do lamina I neurons project? (superficial layer)
Spinothalamic tract.
What is hyperalgesia?
Amplification of pain.
What is peripheral sensitization? How is it caused?
Increased responsiveness to lower-levels of nociceptor activation. Due to modifications of ion channels by phosphorylation. Reduction in voltage needed to open ion gates.
Generally, where in the lamina is pain perceived?
In the superficial.
What is the “wind-up” centralization sensitization?
A noxious stimulus that it frequency dependant, increases sensitivity and greater response.
What is the “activity-dependent CS” central sensitization?
A barrage of conditioned stimuli (noxious) to mimic tissue injury. When followed by an A-beta stimulus, there is the same painful response.
What are the three dimensions of pain?
- Sensory discriminative
- Affective-motivational
- Cognitive-evaluative.
What are the two major pain pathways from the spinal cord to the brain?
Spinothalamic tract and spinoreticular tract.
What are three ways that peripheral pain is treated?
- Anesthetics (codeine derivatives) that block sodium channels.
- NSAIDs that block the production of prostoglandins (inflammation).
- Opiods that inhibit pain response by preventing sensitization.
How do you treat central pain?
Drugs that target opiod receptors and calcium channels to prevent hyper excitatory transmitters.
Antidepressants increase 5HT levels which can inhibit spinal neurons.
