Pain Flashcards
What is nociception?
The sensory response to a noxious stimulus
What is pain?
The perception of nociceptive sensory information
What is congenital indifference to pain?
Congenital condition where a person is not responsive to pain
What are the two dimensions of pain?
- sensory-discrimination
2. motivation-affective
What is the sensory-discrimination part of pain?
perception of exteroceptive (external) or enteroceptive (internal)
noxious information and ‘localization’ of the site.
What is the motivation-affective aspect of pain?
emotional and sympathetic responses and associated (learning) behaviors
What are the three types of pain?
- Physical
- Inflammatory
- Neuropathic
What is the main part of the brain that is associated with the sensory-discriminatory part of pain?
Primary and secondary somatosensory cortices
What are the main part of the brain that is associated with the motivation-affective part of pain?
Frontal cortex
Limbic system
Brainstem areas
What are the three functions of the sensory-discriminative component of pain?
- location
- Intensity
- Modality
What are the two components of the emotional component of pain?
Negative impact on affect/mood
Chronic pain accompanied by depression
How fast is acute pain felt?
0.1 sec after initiation of stimulus (very fast)
What is the fiber type that conducts pain?
A-delta fibers
How adaptive is physiologic pain?
Very–as tissue heals, pain lessens
What is the initial type of pain sensations that are felt?
Sharp, prickling, electric sensation
What is pathologic pain?
Chronic pain
When does pathologic pain begin?
> 1 sec after the stimulus, then increases slowly
How can pathologic pain become maladaptive?
Persistence even without tissue damage
What type of fibers carry pathologic pain? Is this fast or slow conducting?
C fibers
Slow conducting
What are the sensations felt with pathologic pain?
Dull, throbbing, aching, nauseous senstion
What is the function for nociception? Inflammatory?
Nociception = warning Inflammatory = promotes healing
What is dysfunctional pain?
Pain without understanding or the origin
What is neuropathic pain?
Pain d/t damage to nerves
What is the function of neuropathic pain?
It has no protective function
What are the two types of somatic pain? What is the quality of the pain for each? Well or not well localized?
Superficial pain (sharp, well localized) Deep (dull, poorly localized)
What are the fibers that carry superficial pain (initial and delayed)?
A delta intially, followed by C fibers for delayed
Where is deep pain felt?
CT, bones, joints, muscles,
What type of fibers carry visceral pain?
C fibers
What type of pain follows a dermatomal distribution?
Visceral
What are the four processes of pain processing?
- Transduction
- Transmission
- Modulation
- Perception
What is transduction?
sensation taken in from receptors, transmitted
What are the nociceptors for pain?
Free nerve endings
Do pain neurons have a high or low threshold? Do they adapt slowly or fast?
High threshold
Slowly adapt
What are the three stimuli that nociceptors respond to?
Mechanical (nociceptive)
Thermal
Chemical
Free nerve endings that innervate the body go where (where are the cell bodies)? Face?
Body = spinal ganglia Face = trigeminal ganglia
What is the first process that occurs with damage?
Nociception via direct activation of:
- open cation channels
- Membrane depolarization
- Generate action potential
What is the major mediator of pain? Other two? (“inflammatory soup”) What do these do?
Bradykinin
5HT
Prostaglandin
These interact with primary afferent neurons near the site of pain to release other substances
What is the MOA of substance P, which is released in response to a painful stimulus? (What is the effect on blood vessels, and on the immune system)?
Vasodilation and inflammation
Mast cell release of histamine
What is the indirect sensitization of the peripheral nociceptive processing?
Lowered threshold of nociceptors
What is peripheral sensitization?
Spreading of the action potential over other areas where membrane is at a resting state
What does peripheral sensitization lead to? (4)
- Increased sensitivity
- Increased receptive field size
- Inflammatory mediators release
- Activation of silent nociceptors
What are the silent nociceptors? What is their function?
nociceptors that only respond to the molecules secreted by other activated nociceptors
Expand the receptive field for the pain stimulus
What is primary hyperalgesia?
Increase response to a stimulus that is normally painful
What is allodynia?
Pain resulting from non-noxious stimulus
What is the triple response of Lewis?
Erythema
Edema
Wheal
What type of pain is nociceptive pain (physiologic or chronic)?
Physiologic
Which has tissue damage, nociceptive pain or inflammatory pain?
Inflammatory pain
Fibromyalgia or IBS is what type of pain? What causes it?
Dysfunctional pain
–no understandable lesion found
Does neuropathic pain have a protective function?
No
True or false: neuropathic pain is disproportionate to the intensity of nociceptor activation
True
What are the receptors utilized for thermal stimuli?
TRP
What is the axon reflex?
Activation of the sympathetic system in response to pain
Activator of pain, or sensitizer: K
Acivator
Activator of pain, or sensitizer: prostaglandins
Sensitizer
Activator of pain, or sensitizer: hydrogen
Activator
Activator of pain, or sensitizer: substance P
Activator
Activator of pain, or sensitizer: leukotrienes
Sensitizer
Activator of pain, or sensitizer: ATP
Sensitizer
Activator of pain, or sensitizer: bradykinin
Activator
What are the type of fibers that sense mechanical sensations (2)? Which has a high threshold, and which a low?
A-alpha = low threshold A-delta = high threshold
What is the type of fiber that senses heat, chemical, and other multimodal stimuli? Do theses have a high or low threshold? Fast or slow fibers?
C fibers
High threshold
Slow conduction
