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Flashcards in Physiology Deck (13):
1

Nociceptive Pain

Intense stimuli e.g thermal, mechanical, chemical

2

What order of neurones are nociceptors?

First order neurones, they relay information to second order neurones in the CNS by chemical synaptic transmission

3

Do nociceptors have a high or low threshold?

High (only provoked by intense stimuli)
Inflammatory pain has low threshold

4

What type of pain causes hypersensitivity and allodynia?

Inflammatory pain

5

Pathological Pain

Neuropathic pain is triggered by lesions to the somatosensory nervous system that alter its structure and function so that pain occurs spontaneously and responses to noxious and innocuous stimuli are pathologically amplified

6

Congenital Insensitivity to Pain

A very rare condition, congenital insensitivity to pain (CIP) results due to loss of function mutations (missense or in frame deletions) in the gene SCN9A that encodes a particular voltage-activated Na+ channel (Nav1.7) that is highly expressed in nociceptive neurones

7

Gene that has mutations which gives rise to CIP

SCN9A

8

What does SCN9A encode?

Voltage activated Na+ channel (this particular one is highly expressed in nociceptive neurones)

9

What kind of stimuli do alpha-delta fibres respond to?

Mechanical and thermal
(myelinated)

10

Which type of fibres mediate first pain?

Alpha-delta fibres
C fibres mediate second pain (C fibres are polymodal and unmyelinated)

11

Where are cell bodies of nociceptors contained?

Ganglia

12

Where do the nociceptor dorsal root ganglia lie?

Lateral to the spinal column
(The dorsal root ganglia lie lateral to the spinal column – project centrally to the dorsal horn of the spinal cord and peripherally to the skin, muscle, tendons, joints, internal organs)

13

The nociceptors from which ganglia innervate the viscera?

The Nodose (inferior vagal) ganglia