Pain processing

Question 1

What is the difference between pain and nociception?

Answer 1

Pain is the conscious sensory and emotional experience; nociception is the neural encoding of noxious stimuli.

Question 2

What is the role of acute (normal) pain?

Answer 2

Acts as a warning system for survival, promoting avoidance, rest, and healing.

Question 3

When does acute pain end?

Answer 3

It stops once the noxious stimulus is removed or tissue heals.

Question 4

Where are nociceptor cell bodies located for the body and face?

Answer 4

Body: dorsal root ganglia • Face: trigeminal ganglia.

Question 5

What activates nociceptors?

Answer 5

High-threshold mechanical, thermal, or chemical stimuli.

Question 6

What type of pain do Aδ fibres transmit?

Answer 6

Fast, sharp, well-localised first pain.

Question 7

What type of pain do C-fibres transmit?

Answer 7

Slow, dull, burning second pain.

Question 8

What channels mediate mechanical nociceptor activation?

Answer 8

High-threshold mechanoreceptors (HTM) and TRPA1 channels.

Question 9

Which TRP channels detect temperature changes?

Answer 9

TRPV1/2 for heat and TRPM8 for cold.

Question 10

What substances activate chemical nociceptors?

Answer 10

Exogenous irritants and endogenous inflammatory mediators (e.g. ATP acting on P2X3, ASICs).

Question 11

What neurotransmitter mediates fast nociceptive transmission?

Answer 11

Glutamate acting on AMPA/NMDA receptors.

Question 12

What neurotransmitter causes slow excitatory and vasoactive effects?

Answer 12

Substance P via NK1 receptors.

Question 13

What neuropeptide promotes vasodilation and neurogenic inflammation?

Answer 13

CGRP (Calcitonin Gene-Related Peptide).

Question 14

What are the main ascending pain pathways?

Answer 14

Spinothalamic (STT), Spinoreticular (SRT), and Spinomesencephalic (SMT) tracts.

Question 15

What is the function of the spinothalamic tract (STT)?

Answer 15

Conveys location and intensity of pain to the somatosensory cortex.

Question 16

What is the function of the spinoreticular tract (SRT)?

Answer 16

Produces arousal and emotional/autonomic responses to pain.

Question 17

What is the function of the spinomesencephalic tract (SMT)?

Answer 17

Projects to periaqueductal grey (PAG) and RVM for descending pain modulation.

Question 18

Which laminae receive nociceptive input in the spinal dorsal horn?

Answer 18

Lamina I: Aδ input • Lamina II: C-fibre input • Lamina V: mixed wide-dynamic-range input.

Question 19

What is the trigeminal system responsible for?

Answer 19

Pain and temperature from the face, organised into V1, V2, V3 divisions.

Question 20

What two main components make up the experience of pain?

Answer 20

Sensory-discriminative (intensity, location) and affective-cognitive (emotion, learning, memory).