Pain Flashcards
What is the function of the anterolateral system?
- Pain and temperature
- Gross touch
- Light touch
What is the definition of pain?
Unpleasant sensory or emotional experience associated with actual or potential tissue damage, or described in terms of such damage.
What are the 2 duration classifications of the pain?
- Acute
- Chronic
What causes nociceptive pain?
- Stimulation of peripheral nerve fibers or their receptors that only respond to stimuli approaching or exceeding harmful intensity
What are the 3 modes of noxious stimulation to nociceptors?
- Thermal
- Mechanical
- Chemical
What 3 terms are used to describe the perception of pain?
- Visceral
- Deep somatic
- Superficial somatic
What type of pain is dull, aching, and poorly localized?
- Deep somatic
What type of pain is sharp, well-defined, and clearly located?
- Superficial somatic
What type of pain is diffuse, difficult to locate, and often referred?
- Visceral pain
Why are somatic and visceral pain sometimes confused?
- They share afferent pathways
What is neuropathic pain caused by?
- Damage or disease that affects any part of the nervous system involved in bodily feelings
How is neuropathic pain typically described?
- Burning
- Tingling
- Electrical
- Stabbing
- Pins and Needles
- Funny bone
What is phantom pain?
- Pain felt in a part of the body that the brain no longer receives signals from
Phantom pain is a subtype of which type of pain?
- Neuropathic
What is psychogenic pain caused by?
- Mental, emotional, or behavioral factors
Why are psychogenic pain sufferers sometimes stigmatized?
- Medical professionals and general public think the pain isn’t real
Is psychogenic pain real?
Yes
What is referred pain?
- Pain occurs in an area away from the damaged/ pain site
What are the 2 types of referred pain?
- Myofascial
- Sclerotomic & Dermatomic
What is myofascial pain?
- Trigger points
- Nerve impulses bombard CNS and expresses as referred pain
What is sclerotomic/ dermatomic pain?
Pain in the pattern of a spinal nerve root
Where may the heart refer pain to?
- Upper chest
- Left shoulder
- Jaw
- Arm
Where may the diaphragm refer pain to?
- Lateral tip of either shoulder
Where may the gallbladder refer pain to?
- Right shoulder
- Inferior angle of right scapula
What referred pain may result from a ruptured spleen? What is this called?
- Pain on tip of shoulder
- Kerr’s sign
What may sclerotomic pain of L5 and S1 present as?
Lateral leg and foot pain
What is paresthesia?
- Abnormal spontaneous sensations such as burning, tinging or pins and needles
What is dyesthesia?
- Unpleasant sensation produced by a stimulus that is usually painless
What is anestheisa?
Loss of sensation
What is hypoesthesia?
Partial loss of touch and pressure sensations
What is hyperesthesia?
Increased sensitivity to touch and pressure sensations
What is analgesia?
Loss of pain and temperature sensations
What is hypoalgesia?
Partial loss of pain and temperature sensations
What is hyperalegsia?
- Increased sensitivity to pain sensations
What is myalgia?
Tenderness or pain in the muscles
What is malaise?
General discomfort/ uneasiness
What is causalsia?
Intense, severe burning pain
What is allodynia?
Non-painful stimuli evokes pain
What nerve fibers carry fast pain?
Myelinated a-delta
What nerve fibers carry slow pain?
Unmyelinated C fibers
What neuron transmits pain info to the spinal cord?
Nociceptive neurons
Which type of pain is more localized?
Fast
Is fast or slow pain aching, throbbing, burning?
Slow
What time frame is considered acute pain?
< 6 months
Which type of pain typically has more actual tissue damage?
- Acute
Which type of pain can have no actual damaging or threatening stimulus?
- Chronic
What time frame is considered chronic pain?
> 6 months
What type of nerve fibers is typically responsible for acute pain?
Group III
What are the 2 aspects of the pattern of pain?
- Frequency (firing rate of neuron)
- Intensity (frequency of stimuli acting on neuron)
What types of pain does the specific/ anatomic theory of pain not hold true for?
Neurogenic
Neuropathic
What are the 4 underlying aspects of the neuromatrix?
- Body self
- Sensory
- Affective
- Cognitive
What is the sensory aspect of the neuromatrix?
The actual stimulus
What is the affective aspect of the neuromatrix?
- Emotional or personality influence
What is the cognitive aspect of the neuronmatrix?
Frontal lobes remember pain
What role does the insular cortex play in pain perception?
- Distinguishes pain from other homeostratic emotions (itch, nausea_
What role does the anterior cingulate cortex play in pain perception?
- Motivation
What role does the sensory cortex play in pain perception?
Localizes pain
Do type IV or III fibers react more quickly to pain stimulus?
- IV
What is volume transmission?
Dumping of neurotransmitters
What do the primary afferents of pain synapse on?
- Tract cells
- Inhibitory interneurons that regulate ascending flow of nociceptive input
- Facilitory interneurons that regulate ascending flow of nociceptive input
- Interneurons that mediate local refelxes
What method of communicaiton is used by primary afferents of pain?
- Volume transmission
Which type of pain is more discriminitive? (fast or slow)
Fast
What laminae do fast pain fibers synapse on?
- Lamina 1 and 5 (marginal nuceleus)
What 2 areas do fast pain fibers synapse on in the higher centers?
- Lateral thalamus (VPL)
- Post central gyrus of parietal cerebral cortex
On which laminae do most slow pain neurons synapse?
Laminae 2 and 5
What chemical mediators may cause a slow pain response?
- Histamine
- Prostaglandin
- Substance P
- Other inflammatory mediators
Which type of pain projects laterally? (fast or slow)
Fast pain
Which type of pain projects medially? (fast or slow)
Slow pain
Which type of pain has more interneurons? (fast or slow)
- Slow pain
Which type of pain deals with the affective components of pain? (fast or slow)
Slow pain
Which type of pain gives information regard perception of sharpness, intensity, location of pain? (fast or slow)
Fast pain
Where do the fast and slow pain fibers split during their ascent to higher centers?
- At the brain stem
What is the axon reflex (Why does the skin become red and flare up around the area of the injury)?
- Pain receptors transmit impulses in orthdromic and antidromic directions to neighboring skin, where free nerve endings release substance P binding to arteries, and causing dilation, and also binds to mast cells releasing histamine resulting in fluid accumulation
What is the triple response (in relation to inflammation)?
- Red line
- Flare
- Weal
in response to skin stretching
Which autonomic nervous system causes the redness of inflammation?
Sympathetic
What is peripheral sensitization of primary afferents?
- Nerves become inflamed and fire without reason or stimulus
What are the aspects of peripheral sensitization of primary afferents?
- Receptor sensitivity
- Membrane threshold lowered
- Ectopic firing (random firing)
Why is it so difficult to treat central sensitiization?
- There are so many causes
How may neuronal receptive fields be changed in central sensitization?
- Expanded so that more stimuli acts on one field
How can neuronal activity be altered in central sensitization?
- Increased response to noxious stimuli
How can the glia affect central sensitization?
- Release chemical mediators
How can interneurons affect central sensitization?
- Inhibit neurotrasmission
What is long-term potentiating?
- Stimulation of a cell over time increases it excitability/ and its duration of action
How can central sensitization affect membranes?
Lower thresholds
What is wind-up?
- Dorsal cells activated a lot, they’ll fire more often
What is the origin of the lateral spinothalamic tract?
- Laminae I and V - VII in dorsal horn (nucleus proprius)
Do the fibers of the lateral spinothalamic tract cross?
Yes, at the level of the dorsal horn
What is the extent of the lateral spinothalamic tract?
- Throughout the cord
What does the lateral spinothalamic tract synapse on?
- Lateral thalamus
What is the function of the lateral spinothalamic tract?
- Concious pain and temperature
What is the origin of the anterior spinothalamic tract?
- Laminae III and V/ dorsal horn
Do the fibers of the anterior spinothalamic tract cross?
- Yes, at the level of the dorsal horn
What is the extent of the anterior spinothalamic tract?
- Throughout
What is the termination of the anterior spinothalamic tract?
- Medial thalamus
What is the function of anterior spinothalamic tract?
- Gross touch and pressure
- Maybe pain
What is the origin of the spinotectal tract?
- Laminae I and V
Dot he fibers of the spinotectal tract cross?
Yes
What is the termination of the spinotectal tract?
- Tectum of midbrain
What is the function of the spinotectal tract?
Tectum: Reflexive responses to pain and temperature
Locomotor center/ PAG: Aversise behavior and algesia
What is another name for the spinotectal tract?
Mesencephalic
What is the origin of the spinoreticular tract?
Laminae VI and VII
What is another name for the spinoreticular tract?
- Hypothalamic
- Limbic
Do the fibers of spinoreticular tract cross?
Yes
What is the extent of the spinoreticular tract?
Throughout cord
What is the termination of the spinoreticular tract?
Reticular formation
What is the origin of the spinocervical tract?
- Laminae III and IV
Do the fibers of the spinocervical tract cross?
No
What is the extent of the spinocervical tract?
Throughout cord
What is the termination of the spinocervical tract?
Lateral cervical nucleus
What is the function of the spinocervical tract?
Possibly a secondary tract for Pain and temperature to cerebral levels
What is the function of the spinoreticular tract?
- Reflexive response and state of conciousness
What is the origin of the posterior synaptic dorsal column?
- Laminae X
Do the fibers of the posterior synaptic dorsal column cross?
No
What is the extent of the posterior synaptic dorsal column?
Throughout the cord
What is the termination of the posterior synaptic dorsal column?
The gracillis
What is the function of the posterior synaptic dorsal column?
Visceral pain
Where do the group III and IV afferents of the lateral spinothalamic tract enter the spinal cord? What is their pathway from entrance of the cord to their ascending pathway?
- Enter by the lateral division
- Go up or down 2 segments in Lissauers tract (dorsal-lateral fasciculus)
- Enter dorsal horn
- Synapse on projection cell
- Projection cell crosses over cordl through anterior white commisure
- Ascend as lateral spinothalamic tract
How are fibers added to the lateral spinothalamic tract as it ascends the spinal cord?
- From lateral to medial due to its contralateral - projection
- Arranged from lateral to medial:
- Sacral
- Lumbar
- Thoracic
- Cervical
Where do the two spinothalamic tracts split?
At the brain stem
Which spinothalamic tract is the phylogenetically older?
Anterior spinothalamic
Which spinothalamic tract has more synapses?
Anterior spinothalamic
Which tract constitutes the neo spinothalamic tract? Which tract consitutes the paleo spinothalamic tract?
Neo: Lateral spinothalamic
Paleo: Anterior spinothalamic
Where are phylogenetically newer structures located in the spinal cord?
On the lateral portion
What pathway does visceral pain take up the spinal cord?
Post-synaptic dorsal column
Why is meant by the “post-synaptic” in post-synaptic dorsal column?
A projection cell extends from the neuron in the dorsal horn to the pathway in the dorsal funniculus
What is the Melzak and Wall theory?
The gate theory.
Mechanoreceptor/ group II fibers synapse on the projection cell, inhibiting it
- There requires a stronger stimulus to activate pain projection fibers
What is the origin of descending modulatory sytems?
Periaqueductal gray
What nuclei are stimulated by the periaqueductal gray in the descending modulatory system?
- Lateral tegmental nucleus
- Nucleus raphe magnus
What does the nucleus raphe magnus synapse on in the descending modulatory system?
- Inhibits projection neuron that travel to the dorsal horn
- Excites endorphin interneuron that inhibits a projection cell to the dorsal horn and a-delta fiber
What does the lateral tegmental nucleus synapse on in the descending modulatory system?
- Excites an endorphin interneuron which inhibits projection neuron to dorsal horn and a-delta fiber
What neurotransmitter does the nucleus raphe magnus pathway use? What is the name of the pathway?
- Serotonin
What neurotransmitter does the lateral tegmental nucleus pathway use?
- Norepinephrine
What is the overall effect of the descending modulatory system?
If stimulated, it inhibits pain/ causes analgesia
What is the spinomesencephalic tract?
- Projections of the lateral spinothalamic tract to the periaqueductal gray
Review slides 24 - 27 possibly
24 - 27
