PHRM845-FINAL EXAM

Question 1

What is acute pain?

Answer 1

It is short-lived
-Likely from injury, post-operative flare, or acute damage to a tissue

Question 2

What is chronic pain?

Answer 2

Pain that lasts more than 3 months

Question 3

Appropriate pain assessment and adequate pain management are considered to be standard of care, with pain being the ____ vital sign.

Answer 3

Fifth

Question 4

Functions of pain

Answer 4

-Warning system (to avoid injury/a particular area)
-Aid in repair (hypersensitivity)–becomes sensitive to pain and tells body to avoid the stimulus
-Can be maladaptive (irreversible neuropathy) and may lead to more damage

Question 5

Temporal features of pain

Answer 5

Onset, duration, course, and pattern

Question 6

Intensity of pain

Answer 6

Average, least, worst, current pain
-Utilize pain scales

Question 7

Location of pain

Answer 7

-Focal
-Multifocal
-Generalized
-Referred (comes about from another part of the body; example: MI–> pain distributes down arm)
-Superficial
-Deep
**Opioid induced hyperalgesia (generalized)–chronic use of opioids causes pain to be worse

Question 8

Quality of pain

Answer 8

Helps determine the source of pain
-Inflammatory: throbbing, pulsating (inflammatory)
-Neuropathic: stabbing, shooting, burning, tingling
-Visceral: squeezing

Question 9

Clinical pain assessment

Answer 9

-Pain scale (assesses intensity): for adults and children
-Subjective: abused by drug addicts (seeking out opioid narcotics)
**PAIN IS AN EMOTION AND IMPACTS MOOD

Question 10

Pain circuitry-periphery

Answer 10

-Starts in periphery from trauma or damage
-Receptors are activated and release inflammatory mediators (bradykinin, prostaglandins, and increase K+)
-This causes the afferent neuron to send a signal up to brain

Question 11

Pain pathway

Answer 11

Periphery
Transmission
Activation of CNS at spinal cord
Input
Transmission of pain signal to brain
Modulation

Question 12

Peripheral receptors and channels involved in pain signaling

Answer 12

-Temperature sensitive
~Transient receptor potential cation channel (TRP)–conducts Na, K, and Ca
~TRPV (vanniloid)=heat and spice
~TRPM (Melastatin)=cold and menthol

-Acid sensitive
~Acid sensing ion channel (ASIC)
~Activated by H+ and conducts Na+

-Chemical irritant sensitive
~Histamine
~Bradykinin
**Receptors send info to the spinal cord

Question 13

Pathway of reflex upon painful stimuli

Answer 13

Skin–> afferent nerve/neuron–> spinal cord –> reflex arch bypasses CNS because it does not need CNS processing –> efferent nerve –> muscle to withdraw body part from something

Question 14

Three different pain A-fibers transduce different pain signals. What are they?

Answer 14

Aβ-fibers
Non-noxious (not pain-producing)
Touch, pressure
Innervate the skin
Faster, (35-75 m/s)
Thick myelin coating
Not involved with pain conduction

Aδ-fibers
Pain, cold
Myelinated (not as thick as Aβ-fibers)
Fast (2-35 m/s)–Not as fast as Aβ-fibers
“First pain”, reflex arc
Sharp, prickly

C-fibers (“prolonged pain”)
Pain, Temp, Touch, pressure, Itch (polymodal)
Unmyelinated
Slow (0.5-2 m/s)
“Second pain”
dull, aching

Question 15

Peripheral sensitization

Answer 15

Repeated stimuli reduces firing threshold–>gives heightened pain response. Easier for pain firing neuron to conduct action potential.

Increases expression of pain receptors (sensitization)–send more signal into spinal cord (ex: sunburn is sensitive to touch)

Question 16

Substance P’s role in peripheral sensitization

Answer 16

**One of the neuropeptides release when there is an injury
1.Vasodilation
2. Degranulation of mast cells
3. Release of histamine
4. Inflammation and prostaglandins

Question 17

Pain circuitry-spinal

Answer 17

-Possibly enhanced expression of sodium channel subtypes contributing to
~enhanced cellular excitability
~generation of ectopic action potentials

Question 18

Pain circuitry-brain

Answer 18

-Conduction from spinal cord to brain for processing
-High expression of opioid receptors in the brain stem along the descending pathway

Question 19

Which receptor is the most important in pain modules?

Answer 19

Mu opioid receptor

Question 20

Impact of mu opioid receptor activation

Answer 20

-Brain
~Alter mood
~Produce sedation
~Reduce emotional reaction
-Brainstem
~Increase activity of descending fibers
-Spinal cord
~Inhibit vesicle release
~Hyperpolarize post-synaptic membrane
-Periphery
~Reduce activation of primary afferent
~Modulate immune activity

Question 21

How does the somatosensory cortex process pain?

Answer 21

Registers which body part is in pain and the intensity of that pain. Less activity here when patients focus their attention away from their pain.

Question 22

How does the amygdala process pain?

Answer 22

Anticipates pain and reacts to perceived threats

Question 23

How does the prefrontal cortex process pain?

Answer 23

Processes pain signals rationally and plans action. Activated when trying to consciously reduce pain.
Decision-making

Question 24

How does the right lateral orbitofrontal cortex process pain?

Answer 24

Evaluates sensory stimuli and decides on response, particularly if fear is involved. Mindfulness meditation calms down this response.
**Decision making

Question 25

How does the nucleus accumbens process pain?

Answer 25

Releases DA and 5HT during pleasure or pain
**Important area for addiction