Wk 4 Pain Flashcards
Pain
complex experience
- dynamic interactions between physical, cognitive, spiritual, emotional, and environmental factors
Acute pain is protective
promotes withdrawal from painful stimuli, allows injured parts to heal, and teaches avoidance
Chronic pain is not
protective
Neuroanatomy of pain
3 parts of the nervous system involved in the sensation, perception, and response to pain
1. Afferent pathways
2. interpretive centers
3. efferent pathways
Afferent pathways
begin in the peripheral nervous system and travels into the spinal gates and ascends into the cortex of your brain
Interpretive centers
the cortical and subcortical areas of the brain, brain stem, midbrain, and cerebral cortex, this interprets the sensation
Efferent pathways
messages that descend back down and illicit our physical or mental response to the pain
Nociception
afferent pathways, interpretive centers, and efferent pathways = process of nociception
Nociceptors
pain receptors or sensors
Nociceptive stimuli
stimuli of a certain intensity that cause, or are close to causing tissue injury
- receptors response to sharp objects, electric currents, application to heat or cold to the skin
- may also respond to chemical stimuli - acids, etc
- with low intensity -> may not be activated
unevenly distributed throughout our body
Neurotransmitters
chemical messengers that modulate control related to the transmission of pain impulse
- excitatory or inhibitory = can enhance or inhibit pain, stops the pain or increases
Endorphins
type of neurotransmitter
- natural neurochemicals or endogenous opioids that aid in inhibiting the pain response
- produce sense of exhilaration which dulls the pain
4 phases of nociception
Transduction
Transmission
Perception
Modulation
Transduction
painful stimuli is converted to action potential at the sensory receptor
- occurs along A-delta fibers and C fibers
- Substances/chemical mediators released as a result of direct injury and inflammation
- prostaglandin = important mediator than when activated LOWERS the pain threshold
A-delta
- small diameter
- myelinated = rapid transmission of pain
- well-localized
- sharp, stinging, cutting, pinching that is really well localized
C fibers
- smaller diameter
- unmyelinated = slow transmission of pain
- poorly localized
- lots in our body, in our muscles, tendons, skin
- dull, aching, burning sensation, constant
Transmission
process where action potentials move from peripheral receptors to the spinal cord and then the brain
- conduction of a pain impulse along the A-delta and c fibers into the dorsal horn of the spinal cord
- a-delta and C fibers are responsible for the transmission of this message
Perception
brain then receives these signals and interprets them as painful
- our conscious awareness of the pain
Factors that influence perception
- attention
- distraction
- anxiety
- fear
- fatigue
- previous experiences and expectations
Pain tolerance
greatest intensity of pain a person can handle
- varies greatly over time
Pain threshold
lowest intensity of pain that a person can recognize
- perceptual dominance occurs = pain at one site can mask pain at another site
Opioid tolerance
state of adaptation that happens in our body in which exposure to an opioid medication causes change in the drug receptors that results in reduced drug effects over time
Modulation
synaptic transmission of pain signals is altered
- can be amplified or dampened
- endorphins mediate pre-synaptic transmission
- morphine mimics the effect of endorphins
Gate Control Theory of Pain
theory that if we can BLOCK the pain BEFORE it gets to the brain, we can STOP or LOWER pain perception
- touch, rubbing skin, massage, distraction acupuncture, getting active
