Pain

Question 1

what is nociception

Answer 1

• sensory detection of noxious stimuli
• free nerve endings detect stimuli

Question 2

types of free nerve

Answer 2

Mechano
Mechano-thermal
Polymodal

Question 3

Nociception pathway

Answer 3

1.Noxious stimuli occurs
2. Chemical mediators trigger nociceptors
= instigate inflammation

Question 4

Type of nociceptive fibers

Answer 4

1. Delta fibers
   Short, fast pain
2. C fibers
   Slow, dull pain

Question 5

Pain pathway (patho)

Answer 5

1. Primary nociceptive neuron is either delta or C fiber
2. Visceral merge with same secondary neurons as somatic nociceptive neurons = referred pain
3. Pain signal gets sent to Secondary sensory neuron sends sensory signal to thalamus
4. Then goes to primary samatosensensory cortex
5. This detects the type, intensity and location
6. Pain also goes to limbic system (emotional response) and prefrontal cortex (gives understanding about pain)

Question 6

when is Pain perception identified

Answer 6

• once signals reach cerebral cortex

Question 7

Pain threshold vs pain tolerance

Answer 7

• Pain threshold: strength of stimuli resulting in AP frequency and signal intensity
• Pain tolerance: subjective unpleasantness percieved (how much it hurts)

Question 8

Different ways body modulates pain:

Answer 8

1. Gate control
2. descending
3. Endorphins

Question 9

Explain gate control in modulation of pain

Answer 9

• primary nociceptive neuron synapse with secondary nociceptive neuron = sends signal to brain
• primary non-nociceptive neuron and possible thermal send signals to brain
• interneuron positively stimulated by non-nociceptive neuron which then inhibit some pain receptors = reduces pain

Question 10

Explain descending in modulation of pain

Answer 10

• interneuron stimulated by signals coming down from brain
• this then causes interneuron to inhibit secondary sensory neuron
  = pain reduced

Question 11

Explain endorphins in modulation of pain

Answer 11

• involved in descending and gate control
• inhibits transmission of signals from primary to secondary nociceptive neurons
• prevents release of neurotransmitters

Question 12

what is Neuropathic pain

Answer 12

• disease of the somatosensory system
  = alters neuronal signalling within pathway
  = pain in absence of nociception or pain unrelated to tissue damage