20.1 NS: Pain Flashcards
What are the types of nociceptors?
Which conduct slowly and which conduct quickly?
C-fibres (slow) and alpha-delta fibres (fast transmission)
What types of fibres do the palm and back of the hand have?
Palm: C-fibres
Dorsum: alpha-delta fibres
Where do these fibres transmit in the spinal cord?
Input to dorsal horn
Second order neurons project to the brain via the …….
Anterolateral tract
Does nociception equal pain?
What is an example of this?
Nope, noxious stimuli withdrawing frog limb without brain involvement
What is pain hypersensitivity?
Amplification of the pain signal
What is TRPV1? Where do we find it?
What happens when it is activated?
A nociceptive transducer (receptor for capsaicin)- detects heat
Ca/Na influx, depolarisation
Are most nociceptors specialised or specific for e.g. heat or cold?
Most, polymodal. Have multiple TRPV1 (acid), TRPA1 (base) etc.
How does sensitization occur?
Where can it occur?
Inflammatory soup changes the threshold for painful stimulation
Peripheral (at terminal)
or
Central sensitisation (at central pathway)
What do hyperalgesia and allodynia mean?
Hyperalgesia: increased response to a normally painful stimulus
Allodynia: painful response to an innocuous stimulus
What is secondary hyperalgaesia?
Enlargement of the area that feels painful (beyond the damage)
What is the difference between neuropathic and dysfunctional pain?
Neuropathic: lesion, neuroimmune response, positive and negative symptoms (due to peripheral nerve damage)
Dysfunctional: no lesion, no inflammation, positive symptoms (migrane, fibromyalgia etc.)
How does drug induced analgesia work? E.g, NSAIDs
Mimic normal activity of descending pathway
What are the cortical areas that modulate psychological perception of pain?
Anterior cingulate
Prefrontal cortex
Insula
