Pain I and II Flashcards
What’s the pain cycle?
Painful dental therapy/ Post-op pain ---> Apprehension --->Avoidance --->Pathology --->Clinical pain then back to painful dental therapy/post-op pain
What is meant by levels of pain?
pain is detected (and is medicated) at many different levels of the nervous system
What is the definition of pain?
…. “is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage” (Merskey, 1986)*
- individual variability - treat it! (pain is not normal)
What are factors affecting the perception of pain?
cultural background emotional state age previous experience fatigue distraction
What are the two (three) different types of pain that can be experienced?
Two (3) different types of pain can be experienced
Acute (transient) Pain:
Pulled muscle, abrasion, cut skin, blunt needle inj.
Persistent (few days-wks); Chronic (3-6mos.) Pain Joint Pain – arthritis, degenerative disease
Lower back pain
Migraine headaches - neuralgia
Disease - terminal cancer
Of all the senses what is the easiest to modify?
pain, use drugs, mind control.
what does the reception of painful stimuli do for the receipient/
Reception of Painful stimuli motivates the recipient to attend to the stimulus (remove it) or else some form of tissue damage may result
What happens if a painful stimuli occurs for a long time? What can higher centers do about incoming pain stimuli?
If the sensation continues for a long time, CNS characteristics may alter (change in mood)
Painful sensations can be modified by higher centres overriding the incoming stimuli to preserve current state
What are the three categories of pain receptors (nociceptors)?
- Mechanical
- Thermal
- Polymodal
What are the mechanical nociceptors like?
both A delta and C fibres
supplied by both myelinated (A delta) & unmyelinated (C type) fibres
A delta fibres may be responsible to what is called the “first pain”
unimodal (will not respond to temperature stimuli)
only responsive to SEVERE forms of stimulation (pin prick, pinching)
What are the thermal nociceptor like?
may be two types (hot vs. cold):
- mainly supplied by C-type fibres
- small latency indicating they are temp responsive
(and not just inflammation indicators)
- may also respond to extreme mechanical stimulation
What are the polymodal nociceptors like?
- respond to a variety of painful stimuli
- thermal, mechanical (pressure) and chemical
exclusively innervated by C-type fibres
thought to transmit “second pain”
What are the four characteristics of a nociceptor?
Four characteristics:
1) must have high threshold for appropriate stimulus
2) must possess small receptor field within tissue
3) must produce persistent discharge during suprathreshold stimulus
4) innervated by small diameter myelinated/ unmyelinated afferent fibres
For the characteristic of a nociceptor of - must have high threshold for appropriate stimulus, what is the difference between A beta and A delta fibers?
- Lower stimulus intensity required at receptor level to elicit response from an Aβ non-nociceptive vs. Aδ and C nociceptive fibres
It’s like if you’re just walking then it doens’t hurt, you can tell there’s pressure, but when you stomp really hard then you start getting all of the other ones and it hurts.
If nociceptors were firing all the time you’d be in pain all the time
For the characteristic of a nociceptor of - must possess small receptor field within tissue what does this mean for nociceptors?
Each single polymodal nociceptor as a very small receptive field (size of receptive field indicated by size of dot in diagram) and only fire when heat stimulus is over 46C
For the characteristic of what does must produce persistent discharge during suprathreshold stimulus mean?
i.e., response dues not “fatigue out” during the stimulus
? Is this like a rapidly adapting or slowly adapting receptor? It is like a slowly adapting receptor because as you apply the stimulus it continues to fire, not when you put it on or take it off it fires.
