Week 10 Flashcards
(23 cards)
What is pain?
“An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”
What is nociception?
The neural process of encoding noxious stimuli
- Noxious stimuli = a stimulus (e.g. mechanical, thermal, or chemical) that is damaging or threatens damage to normal tissue
What is the difference between pain and nociception?
Nociception (INPUT) = noxious stimuli activates nociceptors and sends a message to the CNS (spinal cord and brain).
Pain (OUTPUT) = Interpretation of this message as being harmful or potentially harmful. The perception of an aversive or unpleasant sensation arising from a specific region of the body.
In order for nociception to occur, what 4 physiological processes must occur?
- Transduction
- Conduction
- Transmission
- Perception
What is transduction?
Conversion of a noxious stimulus into an action potential in the peripheral terminals of sensory fibers.
What is conduction?
The passage of action potentials from the periphery along axons towards the central nervous system
What is transmission?
The synaptic transfer of input from one neuron to another
What is perception?
When the sensation is perceived by the brain – decides if there is pain or no pain
What is the role of the spinoreticular tract?
- Transmission of slow pain or visceral pain (pain from organs)
- Dull ache
What fibres are in the spinoreticular tract?
- Predominantly C fibres
What is the reticular formation?
- Network of nuclei in the brainstem that control things like arousal, consciousness, sleep/wake cycle and motivation
- Projections from the spinoreticular tract go into reticular formation
What are the characteristics of A delta fibres?
- Myelinated fibres
- Fast, sharp, and localised pain
- Allows for the precise localisation of pain
What are the characteristics of C fibres?
- Unmyelinated fibres
- Slow, dull aching or burning pain
- Poorly localise pain
- Connection to the thalamus, reticulum formation and limbic structures = emotional and motivational aspect of pain
What are the 3 ways to classify the duration of pain?
- Acute
- Sub-acute
- Chronic/persistent
What are the 3 ways to classify the pathology of pain?
1.Nociceptive pain
2.Neuropathic pain
3.Nociplastic pain
How long does acute pain last?
- Up to 6 weeks
- Resolves once tissue has been offloaded or healed
- Associated with actual or potential tissue damage
How long does sub-actue pain last?
- From 4 -12 weeks
- Associated with actual or potential tissue damage
- Typically indicates delayed healing or complications such as infection
How long does chronic pain last?
- Pain continues beyond typical tissue healing times
- Generally agreed to be pain persistent beyond 3-6 months
What is nociceptive pain?
Pain is typically related to actual or threatened tissue damage (to non-neural tissue)
Designed to protect us from injury or harm - Caused by the activation of nociceptors and subsequent interpretation by the brain as pain.
What is neuropathic pain?
Arises from abnormal neural activity secondary to disease, injury or dysfunction of the nervous system
- Pain may be felt at the site of injury or further away
What is nociplastic pain?
Pain that arises from altered nociception despite no clear evidence of a stimulus that is activating nociceptors
- Absense of disease or lesion to neural tissue
- Often associated with comobidities e.g. chronic illness, stress
What is sensitisation?
When the nervous system upregulates our pain response over a period of time = sensitization