An unpleasant sensory and emotional experience with actual or potential tissue damage, or described in terms of such damage
The sensory process that provides signals that trigger pain
What impacts the way we react to pain?
-previous experience -Stress -Emotional state -Specific location - prior neg experience - injury there -Gentically predisposed to respond a certain way
The study of the anatomical connections of the nociceptive system provides the framework for understanding how all dimensions of pain are registered and interact with the nervous system
A delta Fibers
-Large diameter, lightly -myelinated- fast adapting -Mechanical and thermal -stimulation -Epicritic pain AKA First pain
Small diameter, unmyelinated Thermal, mechanical, chemical stimulation Protopathic pain AKA Second pain
A beta fibers
Mechanoreceptor Respond to touch Distracts - stimulating mechanoreceptors to distract from the nocicpetors from firing away
How the external stimulus is converted to electrophysiological activity -convert external stimulus into an action potential
How information is relayed via the spinal cord to brainstem and thalamus
connection between the thalamus and cortex controls perception and integrates the affective response to pain
Ascending and descending mechanisms to modulate pain
What do mast cells release?
what do the primary nerve afferents (A delta and C fibers) release?
Substance P- facilitatory, causes vasodilation and swelling to the area of injury
What generates an action potential?
in the periphery- the sensory receptors are activated that excited the threshold of being comfortable, its going to release a number of chemicals when there is cellular damage Transduction-Peripheral activation of nociceptors causes a release of chemical substances which influence the degree of nerve activity and intensity of pain sensation
what happens once the nocicpetors are activated?
synapses in the spinal cord (interneurons) connect the signals to new neural pathways.
Interneurons rich in neurotransmitters regulate transmission of impulses Can facilitate or inhibit transmission
Can lead to the activation of a motor neuron that triggers a muscle reflex and the impulse ascends the spinal cord to the brain
how is the sensory cortex (brodmans area 1-3) involved in perception/response of pain?
tells us what type of pain, making sense of what we are feeling
CH 8: Understanding Pain & Its Relationship to Injury75 terms