Pain - Week 3 PBL

Question 1

Difference between pain and nociception?

Answer 1

Pain - unpleasant sensory experience in association with tissue damage

Nociception - neural process of noxious stimuli passing through ascending and descending pathways from spinal chord to corticothalamic networks

Question 2

What are Nociceptors?

Answer 2

Peripheral receptors for pain via A delta and C nerve fibres

Question 3

Describe mechanical neurotransmission

Answer 3

Fibre: fast conducting myelinated A delta
Stimulation: intense pressure
Pathway Spinothalamic tract
Result : sharp fast pain

Question 4

Describe polymodal neurotransmission

Answer 4

Fibre: slower unmyelinated c fibres
Stimulation: multiple
Pathway: spinoreticulsr
Result: slow aching pain

Question 5

Describe thermal Nociception

Answer 5

Fibre: c fibres
Stimulation: extreme hots and colds
Result: thermal detection

Question 6

Where do peripheral neurons enter and leave spinal chord ?

Answer 6

Enter via dorsal horn
Decussation of spinal chord midline
Goes to spinothalamic tract and to thalamus

Question 7

Describe the spinothalamic tract

Answer 7

Ascending pathway
Rapid neutron pathway
Sensory discriminative (where it hurts)

Question 8

Describe the spinoreticular tract

Answer 8

Ascending and descending pathway
SLower neurons
Negative aspect of pain (unpleasant and worrying)

Question 9

Describe how the membrane potential changes in a neuron for electrical transmission

Answer 9

1) resting membrane at -70mv
2) stimulus at threshold of -50mv (all or nothing)
3) depolarisation- Na+ open
4) Repolarisation - K+ channels open
5) refractory period p, hyper polarisation
6) RMP -70mv