Pain & Analgesia Flashcards
What are the 3 forms of pain?
Nociceptive (Acute e.g. sharp prick)
Inflammatory (Prolonged e.g. burn)
Pathological
What are the nociceptors?
Peripheral sensory afferent neurons that are activated by intense harmful stimuli (e.g. thermal, mechanical)
Is nociceptive pain high or low threshold?
High threshold
What can activate inflammatory pain response?
Immune system, injury or infection
What causes pathological pain?
Abnormal nervous system function
How does inflammatory pain effect general sensitivity to pain?
Increases sensitivity
What are the the subtypes of nociceptor?
A-delta
C-fibres
What do A-delta fibres detect?
Mechanical/thermal stimuli
mediate ‘first’ or fast pain
What do C-fibres detect?
‘second’ or slow pain
Are A-delta or C-fibres myelinated?
A-delta fibres
What layer of spinal cord lamina do A-delta fibres terminate in?
1
What layer of spinal cord lamina do C-fibres terminate in?
2
What fibres are responsible for the spinothalamic tract?
A-delta
What fibres are responsible for the spinoreticular tract?
C-fibres
What does the spinoreticular tract trigger?
The emotional/motivational component of pain
What is the spinomesencephalic tract responsible for triggering?
Modulation of pain
Emotional side of pain
Control or inhibition of pain
What is the spinothalamic tract responsible for?
Acts as a ‘warning system’
- Location
- Severity
- Duration
What is the periaqueductal grey responsible for?
Pain control & inhibition
How can analgesia reduce pain?
- Act at site of injury to reduce nociceptor sensitisation
- Suppressing synaptic transmission of nociceptive signals
- Activate descending inhibitory controls (e.g. opiods)
How do NSAIDs reduce pain?
Reducing nociceptor sensitisation
How do opioids reduce pain?
They bind to opioid receptors which act to reduce synaptic transmission
