Nociception

Question 1

What are the fibres that transmit pain?

Answer 1

III (A delta), IV (C)

Question 2

Which type of pain fibres are myelinated?

Answer 2

A delta

Question 3

Do C fibres transmit

a) dull throbbing ache
b) fast sharp pain?

Answer 3

a

Question 4

Do C fibres respond to

a) mechanical stimuli
b) mechanical stimuli and substances released by damaged tissues?

Answer 4

b

Question 5

Different fibres from which ascending pathway synapse in the Rexed’s laminae?

Answer 5

Anterolateral system

Question 6

Where on the Rexed’s laminae do A delta fibres synspase?

Answer 6

The top and the bottom

Question 7

Where on the Rexed’s laminae do C fibres synapse?

Answer 7

Top layer

Question 8

Where do the 1st order neurones from the anterolateral pathway decussate?

Answer 8

In the spinal cord at the tip of the dorsal horn

Question 9

Where do the 2nd order neurones from the anterolateral system synapse?

Answer 9

Ventral posterior lateral nucleus in the thalamus

Question 10

What is peripheral sensitisation?

Answer 10

Making nociceptors more sensitised

Question 11

How do nociceptors become more sensitised?

Answer 11

Lower the threshold

Increase response to noxious stimuli

Question 12

What is the purpose of peripheral sensitisation?

Answer 12

Reduces the likelihood of further damage

Question 13

What causes sensitisation?

Answer 13

Release of chemicals after damage or inflammation

Question 14

What is central sensitisation?

Answer 14

Sensitisation within the CNS.

Alters synaptic strength

Question 15

Where does central sensitisation occur specifically?

Answer 15

AT synapses in the:
Spinal cord
Thalamus
Amygdala
Anterior cingulate nucleus

Question 16

How does central sensitisation occur?

Answer 16

Nerve cells increase Ca2+ levels which activate pathways that form TF which up regulate formation of receptors

Question 17

What is the Gate theory of pain?

Answer 17

Different sensory modalities (touch) interacts with other pathways in the spinal cord (pain).
Branches from touch pathways (interneurones) feed into pain pathways and block pain pathways

Question 18

What fibres transmit information about touch?

Answer 18

1a, 1b, II

Question 19

Where do 1st order neurones of the dorsal column pathway synapse and decussate?

Answer 19

In cuneate or gracile nucleus in medulla

Question 20

In terms of pain what is the function fo the primary somatosensory cortex?

Answer 20

Localisation of pain

Question 21

What would damage to the post central gyrus cause in terms of pain?

Answer 21

Inability to locate pain

Question 22

How does the limbic system relate to pain sensation?

Answer 22

The hippocampus and amygdala are an affective component of pain they induce suffering

Question 23

What is deafferentation?

Answer 23

Damage to afferent nerves causing changes to pathways and causes central sensitisation

Question 24

What is referred pain and what causes it?

Answer 24

Feeling pain away from site of damage.

Caused by convergence of sensory neurones in second order neurones

Question 25

How is pain controlled centrally?

Answer 25

Descending pathways from sensory cortex release endorphins which inhibit pain pathways