Theories Of Pain Flashcards
What is the basis of the Specificity theory?
Pain is a specific sensation with specific pain receptors which transmit signals to a ‘pain centre’ in the brain where it’s received
Doesn’t account for wide range of psychological factors that affect our perception of pain e.g. No sensory or emotional input
Implies pain is the same for everyone
What is the basis of the Intensity theory?
Pain occurs when a stimulus is sufficiently intense rather than the stimulus being a unique pain stimulus
The idea of high emotional input
What is the basis of the Pattern theory?
Sensation of pain is due to a particular pattern of nerve impulses
Nerve impulses generated by receptors in a particular pattern of space/time are perceived by the brain as pain
Most skin receptors are identical - pain is produced by the intense stimulation of these fibres
What is the basis of the Neuromatrix theory?
Pain is a multidimensional experience affected by both sensory input and activity of the NS
Experiences and expectations are integrated in cognitive, affective and sensory perceptions of pain
Understands chronic pain or pain where the relationship between tissue injury and pain is more complex
Input and output of pain
What are the 6 stages of the pain pathway?
1) nociceptors
2) a delta and C fibres
3) dorsal horn of spinal cord
4) spinothalamic tract
5) thalamus
6) sensory cortex
What is the basis of the Gate Control theory?
Interaction between physiological and psychosocial mechanisms- lead to pain perception and response
‘Gate’ in dorsal horn of SC which can be opened or closed to pain info
What is secreted by pain fibres?
Substance P (NT)
What effect do inhibitory interneurones have on the flow of pain?
Inhibit flow when excited by sensory nerve fibres carrying sensory info.
Fibres are larger in diameter than pain fibres- carry sensory info to the synapse so any pain info arriving at same time along thin fibres can be suppressed
How do descending pathways effect the flow of pain info?
Descending pathways from brain connect neurones in SC
Control flow of pain impulses- increase or decrease messages reaching brain
Info excites interneurone- inhibits T neurones
What effect do natural opioids have on pain pathways?
Inhibit T neurones due to inhibitory peptides (NO)
They are released into synapse and combine with receptors on T neurone- inhibiting chemical transmitter substance released from pain fibres from combining with receptors on T neurone
Combine with receptors on pain fibres too- inviting secretion of substance P
