pain physiology - transduction and transmission

Question 1

what is the definition of pain

Answer 1

an unpleasant sensory and emotional experience associated with actual or potential tissue damage

Question 2

what is nociception

Answer 2

the neural process of encoding noxious stimuli `

Question 3

what are examples of noxious stimuli

Answer 3

pressure
stretch
pinch
extreme temperature

Question 4

what is transduction

Answer 4

free nerve endings of the PNS being stimulated to generate an action potential

Question 5

what is transmission

Answer 5

transport of action potential from the PNS to the ANS

Question 6

what are the three classifications of pain

Answer 6

nociceptive, nociplastic, neuropathic

Question 7

what is nociceptive pain

Answer 7

pain that arises from actual or threatened damage to non neural tissue (pain due to activation of nociceptors)

Question 8

what is nociplastic pain

Answer 8

pain that arises from altered pain reception despite no clear evidence of actual or threatened tissue damage causing the activation of nociceptors

Question 9

what is neuropathic pain

Answer 9

pain caused by lesion or disease of the somatosensory nervous system

Question 10

radicular pain is an example of what kind of pain

Answer 10

neuropathic pain

Question 11

what is radicular pain

Answer 11

pain caused by irritation of the sensory root or dorsal root ganglion of a spinal nerve.

this irritation causes ectopic nerve impulses perceived as pain in the distribution (dermatome) of the axon

Question 12

what is allodynia

Answer 12

pain due to stimulus that should not provoke pain

Question 13

what is hyperalgesia

Answer 13

increased pain from a stimulus that normally provokes pain

Question 14

allodynia can be present when a patient is experiencing

Answer 14

severe swelling

Question 15

what is referred pain

Answer 15

pain felt in a part away from the cause of the pain

Question 16

what is sensitisation

Answer 16

increased responsiveness of nociceptive neurons to their normal input

a response to a stimuli that would normally be considered sub-threshold

Question 17

what is the classification of a first order neuron

Answer 17

unipolar

Question 18

what is the classification of a second and third order neuron

Answer 18

multipolar

Question 19

what is a nociceptor

Answer 19

free nerve endings (dendrites)

Question 20

what stimuli do nociceptors respond to

Answer 20

mechanical - excessive pressure, stretch, pinch, sharp pricking
chemical - inflammatory mediators (h+) (protons)
thermal - extreme heat or cold

Question 21

what determines the speed of action potential

Answer 21

axon diameter
degree of myelination

Question 22

A delta type nerve fibres are responsible for transmitting

Answer 22

fast sharp and local pain

Question 23

C type nerve fibres are responsible for transmitting

Answer 23

slow dull achey pain

Question 24

are c type nerve fibres myelinated

Answer 24

no

Question 25

are a delta nerve fibres myelinated

Answer 25

yes

Question 26

what is the myelin sheath made up of in the PNS

Answer 26

schwann cells

Question 27

the indentations in the myelin sheath are called

Answer 27

node of ranvier

Question 28

what is the purpose of the nodes of ranvier

Answer 28

they allow for specialised ion exchange

Question 29

between laminae in the dorsal horn there are

Answer 29

vast interconnections between laminae 1-7

Question 30

the first order neuron is located in?

Answer 30

the dorsal root ganglion (input from body) trigeminal ganglia (input from face)

Question 31

the second order neuron is located in

Answer 31

the dorsal horn

Question 32

where to neurons communicate

Answer 32

at chemical synapses using neurotransmitters

Question 33

at the synaptic cleft, voltage cannot be transferred across the gap, what helps to bridge this gap

Answer 33

neurotransmitters

Question 34

describe neuronal communication

Answer 34

neurons communicate at chemical synapses using neurotransmitters binding of these neurotransmitters to the post synaptic neuron drives ionic flow - this initiates a post synaptic potential (a change in the electrical charge) post synaptic potentials can either be excitatory (EPSP) or inhibitory (IPSP)

Question 35

EPSPs will summate to reach the threshold and then

Answer 35

the neuron will fire