Lect 9 - Pain (Skin Receptors + Sensitization)

Question 1

Meissner Corpuscle
(Location/Size/Adaptation/Modality)

Answer 1

Superficial
Small
Rapid
Vibration

Question 2

Merkel Disk
(Location/Size/Adaptation/Modality)

Answer 2

Small
Large
Slow
Pressure

Question 3

Pacinian Corpuscle
(Location/Size/Adaptation/Modality)

Answer 3

Deep
Small
Rapid
Vibration

Question 4

Ruffini’s Nerve Endings
(Location/Size/Adaptation/Modality)

Answer 4

Deep
Large
Slow
Pressure

Question 5

Free Nerve Ending
Afferent Fiber Type

Answer 5

alpha delta, C

Question 6

Mechanoreceptors (Except what)
Afferent Fiber Type

Answer 6

alpha beta

Exception: Free Nerve Endings

Question 7

Mechanical Nociceptors
Afferent Fiber Type

Answer 7

alpha-delta

Question 8

Thermal Nociceptors
Afferent Fiber Type

Answer 8

alpha delta

Question 9

Polymodal Nociceptors
Afferent Fiber Type

Answer 9

C

Question 10

Mechanical Nociceptors
Size/Adaptation

Answer 10

Large/Slow

Question 11

Thermal Nociceptors
Size/Adaptation

Answer 11

Small/Rapid

Question 12

Polymodal Nociceptors
Size/Adaptation

Answer 12

Large/Slow

Question 13

Warm Thermoreceptors
Size/Adaptation

Answer 13

Large/Slow

Question 14

Cold Thermoreceptors
Size/Adaptation

Answer 14

Small/Fast

Question 15

Alpha-Beta
(Myelinated?/Fibre Diameter/Conduction Velocity/Examples)

Answer 15

Is Myelinated
Large
Fast conduction density
Touch and Pressure Sense

Question 16

Alpha-Delta
(Myelinated?/Fibre Diameter/Conduction Velocity/Examples)

Answer 16

Little Myelinated
Bit Smaller
Medium conduction velocity
Pain and Temperature

Question 17

C
(Myelinated?/Fibre Diameter/Conduction Velocity/Examples)

Answer 17

Not Myelinated
Very Small Fibre Diameter
Very Low conduction velocity
Pain and Temperature Sensation

Question 18

First Pain
(Afferent Fibre Type / Neuron Location / Releases What)

Answer 18

Fast Pain

Alpha-Delta are activated
2nd Order Neurons (Dorsal Horn –> Cortex)
Releases Glutamate at Synapse

Question 19

Second Pain
(Afferent Fibre Type / Neuron Location / Releases What)

Answer 19

C are activated
2nd Order Neurons (Dorsal Horn –> Cortex)
Releases Glutamate + Substance P at Synapse

Question 20

First Pain
(Fibre Type / Dull or Sharp? / Modality / Receptive Field Size)

Answer 20

Sharp
Intense Mechanical / Intense Temperature
Small (Easy to pinpoint pain)

Question 21

Second Pain
(Dull or Sharp? / Modality / Receptive Field Size)

Answer 21

Dull
Polymodal
Large (Can’t pinpoint location)

Question 22

Nociceptive Pain
(Good/Bad)

Answer 22

Good protective pain
Alerts an unpleasant damaging stimulus

Question 23

Inflammatory Pain

Answer 23

Good pain that follows injury
Promotes healing, protects damaged area from further pain

Question 24

Pathological Pain

Answer 24

Bad pain caused by
Initial Nerve Injury
Chronic Inflammation
Idiopathic

Question 25

Neuropathic Pain (What is it?)

Answer 25

Pain that is caused by damage/dysfunction of central/peripheral nerves

Question 26

Neuropathic Pain (How does it feel?)

Answer 26

Burning sensation from the slightest touch or even just on its own Results in Hyperpathia to sensory stimuli

Question 27

Hyperpathia vs Hyperalgsia

Answer 27

Hyperpathia is increased response to sensory stimuli resulting in pain Hyperalgesia is increased response to a painful stimuli

Question 28

Neuropathic Pain (Mechanisms)

Answer 28

Highly sensitive nociceptors (Damaged nerves can have more Na+ channels meaning greater response to NE) Increased Sympathetic response from CNS

Question 29

Primary Hyperalgesia Where Peripheral/Central Sensitization

Answer 29

At area of injury, within normal receptive field of projection neuron Peripheral: Increase Nociceptor Excitation = Stimuli produces greater effect Central: Sensitized projection neuron is more sensitive from inputs of nociceptors

Question 30

Secondary Hyperalgesia Where Peripheral/Central Sensitization

Answer 30

Beyond area of injury, outside normal receptive field of projection neuron Central: Sensitized projection neuron is now more sensitive to inputs outside of normal receptive field

Question 31

Allodynia Peripheral/Central Sensitization

Answer 31

Peripheral: Non-noxious stimuli can activate nociceptor receptors (Lower Threshold) Central: Insignificant inputs from Alpha-Beta afferents can now activate sensitive projection neuron

Question 32

Hyperalgesia (Summary)

Answer 32

Exaggerated response to painful stimuli

Question 33

Allodynia (Summary)

Answer 33

Sensation of pain to normally insignificant stimuli

Question 34

What releases Bradykinin & Substance P

Answer 34

Inflammatory Cells

Question 35

What releases Histamine

Answer 35

Mast Cells

Question 36

What releases Serotonin

Answer 36

Platlets

Question 37

What releases Prostaglandins

Answer 37

Cell membranes

Question 38

Spinothalamic Pathway

Answer 38

Pain/Temperature 1st Synapse in Dorsal Horn Decussates in Spinal Cord (Contralateral) Goes up Spinal Cord Projects to Contralateral Thalamus and into Primary Somatosensory Cortex

Question 39

Referred Pain

Answer 39

Internal Organ Pain is felt on surface of body Primary afferents from Viscera synapse onto 2nd order afferents used by skin nociceptors

Question 40

Referred Pain (Skin and _____)

Answer 40

Skin and Heart have afferents that converge into the same afferent

Question 41

Withdrawal Reflex (Leg Feeling Pain)

Answer 41

Signal does not cross as it does not need higher level processing Extensor is inhibited Flexor is stimulated

Question 42

Withdrawal Reflex (Leg Balancing)

Answer 42

Signal crosses over to activate other leg Extensor is stimulated Flexor is Inhibited