Pain

Question 1

• Pain is protective
– Brings into consciousness the awareness of tissue damage
• Pain doesn’t feel protective
– It is accompanied by motivational and behavioral responses:
• Crying,Fear, Withdrawal

Answer 1

Physiology of Pain

Question 2

– Mechanical nociception
• Mechanical damage to body tissue
– Thermal nociception
• Damage due to temperature exposure
– Polymodal nociception
• General category
• Pain triggers chemical reactions from tissue damage

Answer 2

(pain perception) NOCICEPTION

Question 3

conveys information about the senses to and from the brain[all motor nerves to skeletal muscles]

Answer 3

Somatic nervous system

Question 4

convey info about the sense organs to the CNS

Answer 4

Afferent (sensory) neurons

Question 5

convey info from CNS to muscles, organs, and glands

Answer 5

Efferent (motor) neurons

Question 6

connect sensory to motor neurons

Answer 6

Interneurons

Question 7

all motor nerves to smooth and cardiac muscles, galnds

Answer 7

autonomic system

Question 8

Nociceptors in peripheral nerves first sense ____

Answer 8

injury

Question 9

In response, release chemical messengers

which travel to spinal cord and brain ,____ neurons

Answer 9

afferent

Question 10

Brain regions identify the site of the injury and

send messages back down spinal column, ____ neurons

Answer 10

efferent

Question 11

• Leads to muscle contractions, helps block pain
• Changes in other bodily functions, such as
breathing

Answer 11

nociceptors

Question 12

• Acts in spinal cord

* Involved in the transmission of pain impulses from peripheral receptors to the CNS

Answer 12

Substance P

Question 13

• Acts in spinal cord
• Amplifies pain signal transmitted from spinal cord to brain
• Implicated in chronic pain

Answer 13

– Glutamate

Question 14

• Released by tissue damage

* Prolong the experience of pain by continued stimulation of nociceptors

Answer 14

Bradykinin & prostaglandins

Question 15

• Released by the immune system to signal the nervous system
• Produce responses such as decreased activity, increased fatigue, increased pain sensitivity
• May sensitize structures in the dorsal horn of the spinal cord to promote the development of chronic pain

Answer 15

Inflammatory cytokines

Question 16

Head and neck pain is directly transmitted to

brain via the 12 ____ nerves

Answer 16

cranial

Question 17

For the rest of the body, the peripheral nervous

system must send impulses to the brain via ___ ___

Answer 17

spinal cord

Question 18

small, myelinated fibers that transmit sharp
pain
• Especially mechanical or thermal pain
• Regulate sensory aspects of pain by projecting onto areas of the
thalamus and sensory areas of the cortex

Answer 18

A-DELTA fibers

Question 19

– large, myelinated fibers
• Conduct impulses 100x faster than C-fibers
• Easily stimulated

Answer 19

A-BETA fibers

Question 20

– unmyelinated fibers transmit dull, aching pain
• >60% of all sensory afferents
• Require more stimulation
• Polymodal pain
• Regulate affective and motivational elements of pain by projecting onto thalamic, hypothalamic, and cortical areas

Answer 20

C-fibers

Question 21

• Primary & secondary somatosensory cortices
• Anterior cingulated cortex (ACC)
• Thalamus
• Cerebellum

Answer 21

Brain areas involved in pain:

Question 22

– The affective dimension of pain
– Feelings of unpleasantness and negative emotions
– Psychological and neural mechanismsinvolved
– Processed in the cerebral cortex are involved in
cognitive judgments about pain

Answer 22

Secondary Affect

Question 23

Electrical stimulation of a rat’s brain produced a

high level of analgesia

Answer 23

– The rat did not feel the pain of surgery
• Conclusion: The brain can control the amount of
pain experienced

Question 24

-substances like heroin or morphine,
but they are produced by the body
• These substances constitute an internal painregulation system

Answer 24

opioids

Question 25

– Produce peptides that project to the limbic system, | brain stem, & elsewhere

Answer 25

Beta-endorphins

Question 26

– Peptides that have widespread neuronal, endocrine, & CNS distributions

Answer 26

Proenkephalin

Question 27

– Found in the gut, the posterior pituitary, & the brain

Answer 27

Prodynorphins

Question 28

• Highly complex system (receptor sensitivity) • Important in natural pain suppression • Must be triggered – Released by stress (Stress-Induced Analgesia) • Suppress immune functioning • Also implicated in cardiovascular control • used for treating chronic pain

Answer 28

endogenous opioid peptides

Question 29

• Typically results from a specific injury – Wound or broken limb • Disappears when damaged tissue is repaired • goes on for six months or less • During there is an urgent search for relief

Answer 29

acute pain

Question 30

``` – Typically begins with an acute episode – Pain does not decrease with treatment – Pain does not decrease as time passes • Three types : – benign pain – recurrent pain – progressive pain ```

Answer 30

chronic pain

Question 31

``` – Persists more than 6 months – Varies in severity – Any number of muscle groups – Relatively intractable to treatment – Ex: Chronic low back pain & myofacial pain ```

Answer 31

Chronic benign pain

Question 32

– Intermittent episodes of acute pain – Chronic because the condition lasts more than 6 months – Ex: Migraine headaches & TMJMD

Answer 32

chronic recurrent pain

Question 33

``` – Increases in severity over time – Persists longer than 6 months – Typically associated with malignancies or with degenerative disorders – Ex: Rheumatoid arthritis & cancer ```

Answer 33

Chronic progressive pain

Question 34

Chronic pain may result from a predisposition to respond to a bodily insult with a specified bodily response

Answer 34

Prechronic pain – most crucial stage – Time between acute and chronic pain – Do you get better? – Do you develop chronic pain?

Question 35

* To soldiers, pain means, “I’m alive” | * To civilians it interrupts activities

Answer 35

Beecher’s study of WWII injuries

Question 36

``` – Classical conditioning • Dentist office, hospital – Operant conditioning • Rewards for pain behaviors may promote development of chronic pain – Attention, sympathy, relief from normal responsibilities, disability compensation – Secondary gains – Personality – Psychopathology ```

Answer 36

individual diff of experience of pain

Question 37

– Specific pain fibers and pain pathways exist, making the experience of pain virtually equal to the amount of tissue damage or injury – Pain is a physical experience largely uninfluenced by psychological factors – In reality, specificity is limited – Pain is a complex, multidimensional phenomenon

Answer 37

Specificity Theory

Question 38

– Structures in the spinal cord act as a gate for the sensory input that the brain interprets as pain • Increase pain (open gate) • Decrease pain (close gate) – Gate located in substantia gelatinosa in the dorsal horn • A-delta, A-beta, and C fibers regulate the “gate” – Central control trigger consists of nerve impulses that descend from the brain and regulate the “gate” • Periaqueductal gray matter supports this theory • Affected by beliefs & prior experience

Answer 38

Gate Control Theory

Question 39

– Extension of Gate Control Theory – Stronger influence of the brain in pain perception – The neuromatrix is a network of brain neurons that processes sensory information but can act even in the absence of sensory input (e.g., phantom limb)

Answer 39

Neuromatrix theory

Question 40

* Rating scales * Large informal vocabulary * Questionnaires

Answer 40

Measuring Pain - Verbal Reports

Question 41

• Multidimensional Pain Inventory – Pain characteristics, interference with lives and functioning, mood

Answer 41

Measuring Pain: Self-report

Question 42

• Dysfunctional – Higher pain, interference & distress, lower activity • Interpersonally distressed – Support persons not providing necessary support • Adaptors – Lower pain, interference & distress and higher functioning • Repressors – Report high pain & low activity but report low distress

Answer 42

Group patients into 4 categories for multidemensional pain inventory

Question 43

• Beck Depression Inventory (BDI) – Chronic pain patients present with a different profile than do depressed patients without pain • Symptom Checklist 90-Revised (SCL-90-R) – Can differentiate between pain patients and people pretending to have pain

Answer 43

Measuring Pain: Standardized Tests

Question 44

``` ___ ____are behaviors that arise as manifestations of chronic pain – Distorted gait or posture – Facial/audible expressions of distress – Avoidance of activities ```

Answer 44

pain behaviors

Question 45

– Measures muscle tension | – Little relationship with self-report pain

Answer 45

Electromyography (EMG)

Question 46

Hyperventilation, blood flow in the temporal artery, heart rate, hand surface temperature, surface temperature, finger pulse volume, skin resistance level

Answer 46

Autonomic indices

Question 47

• Acute Pain – Advantages: signals injury and promotes healing – Disadvantages: it hurts! – Advantages outweigh disadvantages

Answer 47

• Chronic Pain – No Advantages – Syndromes of pain based on symptoms

Question 48

– Recurrent attacks of pain that vary in intensity, frequency, & duration • Symptoms: loss of appetite, nausea, vomiting, & exaggerated sensitivity to light and sound • 30-50yrs of age

Answer 48

migraine headaches

Question 49

– Muscular in origin, accompanied by sustained contractions of the muscles of the neck, shoulders, scalp, and face – Includes mechanisms in CNS • Symptoms: gradual onset; sensations of tightness; constriction or pressure; highly variable intensity, frequency, and duration; dull, steady ache on both sides of head – 40% of US population affected

Answer 49

Tension headaches

Question 50

– Severe headache that occurs in daily or nearly daily clusters – Symptoms similar to migraines but much briefer, rarely last longer than 2 hours – Localized on one side of the head; the eye on the other side often becomes bloodshot and waters – Men > women at 10:1

Answer 50

Cluster Headache

Question 51

• Very common; 80% of people in US • Most people recover • Those who do not recover develop chronic pain problems • Substantial cost: > $90 billion a year • Causes: – Most frequent: injury or stress resulting in musculoskeletal, ligament, and neurological in the lower back – Infections, degenerative diseases, cancer, stress & psychosocial factors

Answer 51

Low Back Pain

Question 52

• Experience of chronic pain in the absence of a body part • Amputation removes the nerves that produce the impulses leading to the experience of pain but not the sensations • Not limited to limbs, also found with breasts and teeth • Severity and frequency varies • Decreases over time • Cause is debated but evidence supports the Neuromatrix Theory

Answer 52

Phantom Limb Pain

Question 53

– Rheumatoid arthritis • Autoimmune disease characterized by swelling & inflammation of joints, cartilage, bone, & tendons • Can occur at any age & more frequent in women – Osteoarthritis • Progressive inflammation of joints; dull ache • Most common form; especially among elderly

Answer 53

athiritis pain