Lecture 2

Question 1

What is a bottom up driver?

Answer 1

Peripheral driver

Question 2

What is a top down driver?

Answer 2

Supraspinal driver

Question 3

In acute injury, what is the main driver?

Answer 3

Peripheral driver - experience of pain is driven predominantly from nociception in peripheral tissue

Question 4

In chronic injury, what is the main driver?

Answer 4

Most likely supraspinal (central) driver - link between pain and tissue damage is weaker
Any pain experienced less likely to have nociception as dominant driver. Pain mostly upregulated by central sensitisation

Question 5

Describe the peripheral driver mechanisms
(Location, quality, intensity, behaviour, duration, clinical signs)

Answer 5

Location: Precise
Quality: sharp, aching
Intensity: worse with movement
Behaviour: does not spread
Duration: eased quickly with rest
Clinical signs: associated with an injury

Question 6

Describe the central driver mechanisms
(Location, quality, intensity, behaviour, duration, clinical signs)

Answer 6

Location: shifting and spreading
Quality: unusual
Intensity: severe or not affecting by movement
Behaviour: unpredictable
Duration: does not ease quickly with rest
Clinical signs: pain that is not associated with an obvious mechanical driver

Question 7

What are the 3 different sensory afferents?

Answer 7

A-beta fibres
A-delta fibres
C fibres

Question 8

Describe A-beta fibres
(Diameter, myelination, conduction velocity, receptor activation thresholds, sensation on stimulation)

Answer 8

Diameter: large
Myelination: highly
Conduction Velocity: >40ms-1
Receptor Activation
Thresholds: Low
Sensation on stimulation: Light touch, non-noxious, rapid

Question 9

Describe A-delta fibres
(Diameter, myelination, conduction velocity, receptor activation thresholds, sensation on stimulation)

Answer 9

Diameter: Small 2-5um
Myelination: Thinly
Conduction Velocity: 5-15ms-1
Receptor Activation
Thresholds: High and Low
Sensation on stimulation: Localised nociception

Question 10

Describe C fibres
(Diameter, myelination, conduction velocity, receptor activation thresholds, sensation on stimulation)

Answer 10

Diameter: Smallest <2um
Myelination: Unmyelinated
Conduction Velocity:< 2ms-1
Receptor Activation
Thresholds: High
Sensation on stimulation: Slow, diffuse, dull nociception

Question 11

HTMR

Answer 11

Free nerve ending
Epidermis/dermis
Noxious mechanical stimuli

Question 12

LTMR

Answer 12

Pacinian corpuscle
Deep dermis
Vibration

Question 13

Which Lamina do Alpha-Beta fibres synapse on?

Answer 13

Lamina 3, 4, 5

Question 14

Which Lamina do Alpha-Delta fibres synapse on?

Answer 14

Lamina 1, 2 and 5
(1 through 5)

Question 15

Which lamina do C fibres synapse on?

Answer 15

Lamina 1, 2 and 5

Question 16

Where do nociceptors go?

Answer 16

I and II dorsal horn

Question 17

Where do mechanoreceptors go?

Answer 17

III and IV

Question 18

Where do proprioceptors go

Answer 18

V

Question 19

What is nociception?

Answer 19

detection, transmission and processing of noxious stimuli

Question 20

3 forms of energy for nociception

Answer 20

thermal, chemical or mechanical

Question 21

Where is dorsal horn?

Answer 21

back of spinal cord

Question 22

What neurotransmitters are released at the 2nd order neuron

Answer 22

Glutamate, Substance P, Calcitonin

Question 23

2nd order neuron goes to brain via which tract

Answer 23

spinothalamic (thalamus)

Question 24

What is the somatosensory cortex

Answer 24

area in outer part of brain which is associated with touch

Question 25

Bigger areas in somatosensory cortex feel...

Answer 25

more sensation

Question 26

What is the third order neuron in the thalamus responsible for

Answer 26

location and discrimination of pain. locates pain to be within certain area of somatosensory cortex

Question 27

What happens at the dorsal horn?

Answer 27

area of spinal cord where primary afferent fibres synapse with second order neurons

Question 28

What does the premotor/motor cortex do?

Answer 28

organise and prepare movements

Question 29

What does the cingulate cortex do?

Answer 29

concentration

Question 30

What does the prefrontal cortex do?

Answer 30

problem solving, memory

Question 31

What does the amygdala do?

Answer 31

fear, fear conditioning, addiction

Question 32

What does the sensory cortex do?

Answer 32

sensory discrimination

Question 33

What does the hypothalamus/thalamus do?

Answer 33

stress response, autonomic regulation, motivation

Question 34

What does the cerebellum do?

Answer 34

movement and cognition

Question 35

What does the hippocampus do?

Answer 35

memory, spatial cognition, fear conditioning

Question 36

What does the spinal cord do?

Answer 36

gating from periphery

Question 37

What is the Amygdala's relationship for descending pain modulation

Answer 37

modulates pain perception through direct connections with the descending pain inhibitory system

Question 38

Describe Descending pain modulation

Answer 38

Periaqueductal Gray in midbrain --> rostral ventral medulla --> endogenous opiate system --> pain suppressed

Question 39

What is the homunculus

Answer 39

a map along the cerebral cortex of where each part of the body is processed

Question 40

Explain the process of nociception simply?

Answer 40

- Noxious stimuli occurs - chemicals released by immune cells stimulate nociceptors - nociceptors propagate information to dorsal horn (back of spine) - nociceptors release neurotransmitters (glutamate, substance P, calcitonin) to second order neuron at dorsal horn - information travels to thalamus via spinothalamic tract. - 3rd order neuron locates pain to be within certain area of somatosensory cortex