L9 - Pain, nociception and analgesia

Question 1

What’s the pathway for somatosensory perception?

Answer 1

Sensory receptors → Spinal cord → Brainstem → Thalamus → Somatosensory cortex → Other cortical areas

Question 2

What are the 6 types of peripheral sensory receptors?

Answer 2

Free Nerve Endings: Pain, temperature.

Merkel’s Disc: Touch.

Meissner’s Corpuscle: Touch.

Pacinian Corpuscle: Vibration.

Ruffini’s Ending: Stretch.

Hair Follicle Receptor: Mechanical energy to electrical energy conversion.

Question 3

what’s pain?

Answer 3

subjective “feeling” due to a noxious (painful) stimulus

Question 4

what’s nociception?

Answer 4

perception of a noxious stimulus

Question 5

what’s analgesia?

Answer 5

modulation of nociception/ pain

Question 6

what’s transduction?

Answer 6

when a noxious stimulus is converted to electrical activity in the nerve

Question 7

what’s transmission?

Answer 7

electrical signal sent through nerves to the spinal cord and brain

Question 8

what’s perception?

Answer 8

noxious stimulus perceived in the brain and conscious ‘feeling’ of pain

Question 9

what’s modulation?

Answer 9

signal modulated at various levels (analgesia)

Question 10

what are the levels of nociception?

Answer 10

Peripheral Transmission: Nociceptive fibers enter the spinal cord via the dorsal root, terminating in the dorsal horn.

Neurotransmitters: Glutamate and substance P.

Central Transmission: Ascending axons cross the midline, ascend through the anterolateral column of the spinal cord, terminating in the thalamus, with collateral terminations in the brainstem.

Question 11

what are the 2 features of pain perception?

Answer 11

Cingulate Cortex: Likely involved in the perception of pain, activated during imagined pain.

Subjective Experience: Pain is subjective based on nociceptive fiber information.