pain Flashcards
what is pain?
an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage
is there always tissue damage with pain?
no there may or may not have tissue damage
T/F: there are pain receptors in the body
false the correct terms are nocicpetors
which fiber type conduct pain?
a and c fibers
what are c fibers?
they are unmyelinated fibers, create longer lasting and slower pain normally a day or 2 later
what are a fibers?
thinly myelinated create initial pain
what do tissues do?
they tell you what is going on
what makes the final decision?
the brain
which fibers are nociceptive?
C and A delta fibers
what do nociceptive fibers do?
free nerve endings that convey pain, temperature, and crude touch
which fibers are non nociceptive?
A beta fibers
what do non nociceptive fibers do?
touch, pressure, and vibration (fake pain)
what are the three ways for the nervous system to be stimulated?
- mechanically
- thermally
- chemically
T/F: the amount of pain and the severity of an injury do not always correlate with each other
true
ex) painless battle wounds, painless nail in head, and phantom limb pain
what is one of the most common reasons people seek care from physical therapists?
pain
when does pain normally resolve for acute tissue injury and infection?
48-72 hours
T/F: pain isn’t subjective and not always real
False pain is always subjective and always real
what are some contextual factors contributing to the experience of pain?
biological, physical, psychological, occupational, social, cultural, and environmental factors
how do we feel pain?
through ascending pathways
describe the ascending pathway
injury to body
release of cytokines
PGs stimulate C fibers and A delta fibers
C fibers and A delta fibers carry the nociceptive information to the ipsilateral dorsal horn of the spinal cord
at the same time information from surrounding levels are also sensing information that needs to be regulated
where do first order neurons synapse?
on the substantia gelatinosa
first order neurons activates substance P which activates what?
second order neurons which project to the spinothalamic tract
what is sensed in the anterior spinothalamic tract?
crude touch
what is sensed in the lateral spinothalamic tract?
pain and temperature
where do second order neurons ascends through?
spinal cord and the brain stem and projects to the thalamus
what happens in the thalamus?
the second order neuron will synapse on third order neuron
what does the third order neuron project on?
to the primary somatosensory cortex on the left side of the brain
what do the ascending pathways do what?
detect pain
what do the descending pathways do?
control pain
where is nociceptive information sent to?
dorsal horn
do non noxious stimulus get sent to the brain?
no
T/F: interneurons are mainly inhibitory
true
how are touch fibers (A beta fibers) activated?
with light touch, pressure, or vibration
touch receptors send action potentials into where and give off what?
posterior grey horn and give off collateral neurons which synapse on interneurons
what do interneurons release?
gamma aminobutyric acid (GABA)
what does GABA inhibit?
activity at substantia gelatinosa (which inhibits substance P)
what is pain inhibition also known as?
the gate control theory
during the descending analgesic pathway activation of a delta and c fibers produce what?
stimulation of hypothalamus, thalamus, cortex, and amygdala that causes a projection of the periaqueductal grey matter and stimulation of the lotus
projections down to substantia gelatinosa of the dorsal horn when releases?
NE and serotonin to interneurons in dorsal horn
what do interneurons release?
enkephalins, endorphins, and dynorphins which inhibit substantia gelatinosa resulting in decreased pain
what is acute pain?
a natural sensation that warns of possible injury
what is chronic pain?
defined as pain lasting more than 3 months. serves no benefits, cognitive and emotional factors have a critical influence on pain perception
how does central sensitization (allodynia) play a huge role in chronic pain?
with persistent nociception via C fibers, permanent neuroplastic changes are likely to occur, after constant barrage from C fibers, the interneuron may die due to high levels of amino acids. decreased ability to modulate nociception and the pain experience, now everything gets projected to the brain including light touch which may now be painful
what can allodynia result in?
in spreading pain or mirror pain from abnormal synapsing in spinal cord
sensory maps are genetically determined and sculpted based on?
movement and exercising it
what is smudging?
not using a body part therefore losing it
what are central changes that occur with/are caused by pain?
homunculus become blurry
enlarged map
difficulty with L vs R discrimination
what is central processing of persistent pain?
when the brain starts questioning its map, threat level of nervous system goes up and can cause pain or increase pain for a prolonged period of time. this smudging of map causes a ramp ip phenomena of nervous system because the brain wants to know more
how does a stressful situation affect pain and the development of chronic pain?
if you hurt yourself in a high stress environment, you are 8X more likely to develop chronic pain
ex) surgery, car accident, work, abuse
how do sport situations affect pain and the development of chronic pain?
kids who play contact sports in life experience less pain in life
ex) learn injury and pain is normal
How does pain work in the brain and ask if it is being threatened?
potentially novice-give information is sent up to the brain via ascending system and the brain processes this via the neuromatric and asks “am I in danger”
what happens if the brain thinks it is in danger?
it wants to know more information known as facilitation
what happens if the brain doesn’t think it is in danger?
it concludes no threat and we see inhibition
what is occurring when we experience pain and the fight or flight response is active?
adrenocorticotropic hormone (ACTH) is released from pituitary gland to stimulate the adrenal glands to produce adrenaline. cortisol helps to mobilize glucose reserves but can leave you feeling sore, tired, sensitive, and fatigued
how does cortisol affect the immune system?
chronic conditions including stress- 3 immune chemicals seem to be very active. nerves become more sensitive to immune system
what are some effects of long term pain?
fatigue, insomnia, and hypervigilance
