Pain physiology Flashcards
What are the three classifications of pain?
Nocioceptive
Inflammatory
Pathological
What is the definition of pain?
An unpleasant sensory and emotional experience.
What are nocioceptors?
Peripheral primary specific sensory afferent neurones activated by intense noxious stimuli e.g. Chemical, thermal, mechanical etc.
Are nocioceptors first or second order neurones?
First order
What kind of neurones do nocioceptors relay information to and where are they?
Second order neurones in the CNS
Is nocioceptive pain adaptive or maladaptive?
Why?
Adaptive as it is an early warning system that detects and minimises contact with damaging stimuli.
Is nocioceptive pain high or low threshold?
High threshold, it is provoked only by intense stimuli.
What happens when a nocioceptor is activated by noxious stimuli?
It overrides other CNS activities and initiates a withdrawal reflex. It also initiates an emotional response that allows us to remember this and avoid the stimuli in future.
Is inflammatory pain adoptive or maladaptive?
It is adaptive and protective
What other two things can inflammatory pain result in?
Pain hypersensitivity and allodynia (innocuous stimuli now elicit pain)
What is the benefit of inflammatory pain?
Assists in healing of damages area by: discouraging physical contact and movement.
Is inflammatory pain high or low threshold?
Low threshold in order for tenderness to promote healing.
What is adaptive pain?
Helpful pain that will encourage behaviour that aids healing.
Is pathological pain adaptive or maladaptive?
Maladaptive, it has no protective function
What are the two categories of pathological pain?
Neuropathic and dysfunctional.
What is neuropathic pain?
Caused by damage or disease affecting the somatosensory nervous system.
What two things is pathological pain associated with?
Spontaneous pain and pain hypersensitivity.
What is dysfunctional pain?
A pain where there is no obvious neural lesion or inflammatory pain.
What causes congenital insensitivity to pain?
Rare condition resulting in loss of function mutations e.g. Missense in gene that encodes Na channels that are highly expressed in nocioceptive neurones
What are the symptoms of CIP?
Lip and tongue injury, bruises and cuts, multiple scars, bone fractures, joint deformity and premature mortality.