L3 Somatosensation/Pain Flashcards

Question

Nociceptors vs Thermoceptors

Answer 1

Action potentials are fired at same rate at all temps at thermoreceptor number and frequency of firing increase at nocicoceptors

Answer 2

Found in peppers, activates responses in C fibers the less TRPV1 receptors you have, the more spice you can handle

Answer 3

1. Free nerve ending 2. Lissauers Tract* 3. Decussate in ventral commisure 4. Synapses in Medulla, Pons on RF and Midbrain on PAG 5. Remaining fibers travel up and synapse in thalamus on MD, VPL, VMP 6. MD --> Cingulate gyrus, VPL --> SI, VMP --> insula * some fibers travel up to raphe nuclei to then synapse on the PAG

Answer 4

descriptive divisions of spinal gray matter in cross section process and transmit sensory info, coordinate motor functions C fibers will terminate on Rex I/II A delta will terminate on Rex I/V I/V = brainstem and thalamic Non-nocioceptive = III/IV/V

Answer 5

Multimodal lamina V neurons are known as this some receive visceral sensory input as well as pain inputs could be an explanation for referred pain

Answer 6

Unilateral spinal cord lesion Loss of ALS (pain, temp, itch) on CONTRALATERAL side Loss of DCML (sensation, touch, pressure, etc) on IPSILATERAL SIDE this is because in the ALS the 2nd order neurons in I and V cross midline and ascend to brainstem vs DCML, they cross in medulla

Answer 7

gives us location, intensity, quality of noxious stimuli Depends on info relayed through the VPL to S1 and S2 ALS tract manages it

Answer 8

unpleasant feeling, fear, anxiety, fight or flight response targets: reticular formation, PAG, superior colliculus, parabrachial nucleus

Answer 9

processes and relays second pain to amygdala, hypothalamus, thalamic nuclei help to elaborate affective-motivational aspects of pain

Answer 10

ALS is capable of mediating something like nondiscriminative touch, but stereognosis is impaired and it lacks fine spatial resolution C fibers do this

Answer 11

responsible for innocuous temperature sensation, which are mediated by fibers that don't respond to noxious stimulus or mechanical stimulation, just change in temp cells in lamina 1 cause the actions that relate to homeostasis

Answer 12

following a painful stimulus that caused tissue damage stimuli in area of injury are seen as significantly painful, when they should be slightly painful

Answer 13

results from interactions nociceptors with the inflammatory soup of substances released at tissue damage heightened sensitivity of nerve endings and an increased responsiveness to pain signals These substances/molecules cause the nerve endings to become sensitized, making them more likely to respond to low level stimuli

Answer 14

protecting the injured area promote healing guard against infection

Answer 15

rapid onset, activity-dependent increase in the excitability of neurons in the dorsal horn of the spinal cord triggered by activity at nociceptors in dorsal horn causes increase in pain and sensitivity in the CNS causes subthreshold levels of activity to be sufficient to generate APs in dorsal horn neurons

Answer 16

induction of pain by a normally non-painful stimulus occurs immediately after painful event and can outlast the pain of the stimulus by several hours

Answer 17

Windup progressive increase in the discharge rate of dorsal horn neurons in response to repeated low-frequency activation of nociceptive afferents. EASIER: refers to an amplified and prolonged pain response in the spinal cord lasts only during stimulation and happens b/c of summation of slow synaptic potentials the delta stimulus remains strong because there is a increased sensitivity to glutamate

Answer 18

when afferent nerve fibers or central pathways are damaged, sensitization can persist causing neuropathic pain can arise without stimulus or can be produced by a mild stimulus constant burning sensation that can have shooting, stabbing, or jolts no inflammation process

Answer 19

most common cause of chronic pain syndromes possibly due to maladaptive plasticity in neural circuits reorganization of mapping/neural plasticity, residual nerve activity, central sensitization can cause it

Answer 20

1. PAG--> can produce analgesia, inhibits nociceptive neurons in dorsal horn of SC 2. Parabrachial nucleus, dorsal raphe, locus ceruleus, medullary RF --> release NTs that can excite or inhibit neurons 3. Descending tracts--> excite or inhibit dorsal horn, impact efficacy of nociceptive transmission 4. Interactions between mechanoreceptive afferents and neural circuits (rubbing toe after hitting it)

Answer 21

flow of nociceptive info through the SC is modulated by activation of large myelinated fibers of low-threshold mechanoreceptors

Answer 22

responses can be blocked by antagonist opioids (in the example of pain medication), there is a physiologic basis for pain relief experienced--pts pain is real causes activation of endogenous opioid receptors, also can activate descending pathways which modulate pain

Answer 23

located in the PAG three types: enkephalins, endorphins, dynorphins areas of the nervous system that produce analgesics are very receptive to opioids, meaning there are opioid sensitive neurons these substances reduce the level of activity passed onto higher processing centers

Answer 24

thought to decrease the release of neurotransmitters, so essentially modulating neuronal excitability cannabinoids can block the electrical stimulation of the PAG, stopping pain signals from traveling elsewhere noxious stimuli cause increased cannabinoids in PAG

Answer 25

1. pain inhibition, causes release of opioids 2. Descending tract modulation 3. Modulates emotional response to pain 4. Placebo effect 5. Integrates sensory and emotional information to modulate pain

L3 Somatosensation/Pain Flashcards

(50 cards)