Test 2: lecture 16 pain

Question 1

Pain is a subjective ____sensory or ____experience associated with actual or potential tissue damage

Answer 1

unpleasant

emotional

Question 2

nociception

Answer 2

pain requires awareness

(need to be conscious)

Event of sensing mechanical, chemical and thermal stimuli, which have the ability or the potential ability to cause damage to the tissues

Physiologic process of sensing, encoding, and transducing a noxious stimulus

Question 3

Physiologic process of sensing, encoding, and transducing a noxious stimulus

Answer 3

nociception

Nociception is the detection of painful stimuli.

Question 4

Nociceptors are free nerve endings of ___fibers

Answer 4

Aδ and C

Question 5

____ Encode physical insults into electrical signals and
transduce them to the dorsal horn of the spinal cord

Answer 5

nociceptors

Question 6

Nociceptors can lower their activation threshold following repeated stimulation, which results in____

Answer 6

peripheral sensitization

easier to trigger pain that more it happens

Question 7

peripheral sensitization

Answer 7

easier to trigger pain pathway the more you repeat the stimulation

Question 8

1st order pain pathway

Answer 8

Nociceptors → spinal cord

Question 9

2nd order pain pathway

Answer 9

spinal cord → thalamus

Question 10

3rd order pain neurons

Answer 10

thalamus → somatosensory cortex

Question 11

pain pathway

Answer 11

Nociceptors → spinal cord

spinal cord→ thalamus

thalamus→ somatosensory cortex

Question 12

3 types of 1st order pain neurons

Answer 12

Mechanothermal afferents Aδ fibers (Thermal and
mechanical stimuli)

2. Polymodal afferent C fibers (Thermal, mechanical
   and chemical stimuli)
3. High threshold mechanoreceptive afferents Aδ fibers
   ( respond to intense mechanical stimuli)

Question 13

___ type of 1st order pain neurons respond to thermal and mechanical stimuli

Answer 13

Mechanothermal afferents Aδ fibers

Question 14

___ type of 1st order neurons respond to thermal, mechanical and chemical stimuli

Answer 14

Polymodal afferent C fibers

Question 15

___ type of 1st order neurons respond to intense mechanical stimuli

Answer 15

High threshold mechanoreceptive afferents Aδ fibers

Question 16

___ are fast conduction, have myelin and are for sharp & pricking pain

Answer 16

Aδ fibers

Mechanothermal afferents Aδ fibers (Thermal and mechanical stimuli)

High threshold mechanoreceptive afferents Aδ fibers ( respond to intense mechanical stimuli)

hit your foot→ first sharp pain you feel, the burning afterwards are C fibers

Question 17

___ fibers are slow conducting, have no myelin and provide a burning type of pain

Answer 17

Polymodal afferent C fibers (Thermal, mechanical and chemical stimuli)

hit your foot→ first sharp pain you feel are Aδ fibers, the burning afterwards are C fibers

Question 18

opioids and NSAIDs work on what type of 1st order neurons?

Answer 18

C type → the burning sensation

Question 19

___ are used to block Aδ fibers

Answer 19

local anesthetics

Question 20

3rd order neurons relay information received from 2 nd order neurons in the thalamus to the ____(awareness)

Answer 20

somatosensory cortex

Question 21

____ will modulate the input from afferent nerve fibers (1st order)

Answer 21

interneurons in the dorsal horn of the spinal cord

Question 22

two major categories of pain

Answer 22

physiologic pain

Normal physiologic function

neuropathic (pathologic) pain

Pathology to nociceptors & conducting pathways

Question 23

acute vs chronic pain

Answer 23

ACUTE PAIN
— Trauma, surgery, infection & inflammation
— Abrupt & Brief
— Alleviated with analgesics

CHRONIC PAIN
— Evolution of acute
— Beyond time for and injury to heal
— Needs more complex analgesic strategy

Question 24

____ extremely sensitive to touch, feather can be painful

Answer 24

allodynia

causes by repetitive stimulation of the same pain pathway, gets easier and easier to trigger

Question 25

\_\_\_ is increased pain from a stimulus that normally provokes pain

Answer 25

HYPERALGESIA

Question 26

allodynia vs hyperalgesia

Answer 26

**Allodynia** is pain due to a stimulus that does not normally elicit pain. **Hyperalgesia** is increased pain from a stimulus that normally provokes pain.

Question 27

plasticity of pain pathways

Answer 27

nervous system can adapt → facilitate learning and memory can lead to central and peripheral sensitization, allodynia and hyperalgesia **Allodynia** is pain due to a stimulus that does not normally elicit pain. **Hyperalgesi**a is increased pain from a stimulus that normally provokes pain.

Question 28

central sensitization vs windup

Answer 28

**central sensitization**→ what happens to a **bunch of neurons** in response to a repetitive stimulus → makes it easier to trigger that event with less stimulus **(global event both ascending and descending pathway)** **windup** → what happens to a **single neuron in the spinal cord** with repetitive stimulus

Question 29

windup is inhibited by \_\_\_

Answer 29

blockade of the NMDA receptors with **ketamine**

Question 30

dysphoria vs pain

Answer 30

**dysphoria** is reaction to drugs that look like pain- thrashing screaming- can be caused by opioids and ketamine, certain breeds are more susceptible **pain**: is in response to a stimulus, will result in increased HR and BP and sometimes aggression

Question 31

3 type of spinal tracts for pain

Answer 31

neospinothalamic paleospinothalamic archispinothalamic tracts.