The pain Experience 2

Question 1

In this diagram show where the pain is dectected, 1st synapse, 2nd synapse and Perception.

Answer 1

Question 2

Where do 2nd order neurones go next?

Answer 2

Across the midline to the Contralateral thalamus

Via trigemino-thalamic tract

Question 3

What can happen at the first synapse?

Answer 3

Interactions between pathways

• Divergence and convergence
• causing Hyperalgesia, radiating and referred pain

Modification of the signal

Question 4

What is going on the the first and second part of this diargam?

Answer 4

Question 5

Why is it difficult to localise dental pain?

Answer 5

Single axons branch to supply more than one tooth pulp.

AND

Single axons branch to synapses with many 2nd order neurones

Question 6

What is Hyperalgesia ?

Answer 6

Hyperalgesia = Increased response to a nociceptive/noxious stimulus. i.e. more pain experienced

Question 7

What is Radiating pain ?

Answer 7

Radiating pain = Pain perceived as originating from a larger area than the stimulus area

Question 8

What is Referred pain ?

Answer 8

Referred pain = pain perceived at a location other than the site of the painful stimulus. Often deep to superficial.

Usually from a deep to superficial structure

Usually segmental:

• Heart to left arm
• Maxillary sinus to teeth
• Appendix to abdominal skin

Question 9

Explain the Gate way controlled theory

Answer 9

Gate control theory

Melzack and Wall, 1965

Was an attempt to explain how pain signals may be modulated.

Gate = Inhibitory interneurones

Interneurones are activated by:

• Segmental inputs
• Descending controls

Question 10

At Synapses there are a number of Neurotransmitters. Give examples of Excitatory and Inhibitory ones.

Answer 10

Excitatory

• Substance P
• CGRP
• Glutamate

Inhibitory

• Endogenous opioids
• Glycine
• GABA

Question 11

What Analgesic (drug acting to release pain) will decrease the release of Substance P, CGRP and Glutamate?

Answer 11

Pregabalin