Pain Flashcards
Which neurotransmitters are involved in the pain pathway? 
• glutamate
• GABA
• serotonin
• endorphins
• dynorphines
• norepinephrine
What happen during the pain pathways
- Sight of injury
- Spinal cord
- Brain stem
- Cerebrum - stomasensory cortex
What is nociception
Encoding an noxious stimuli
this doesn’t always pain patient preserves pain
Which terminals sense the noxious stimuli?
Peripheral sensory terminals
Where is the cell body of the nocieptor located?
• Dorsal hom of spinal cord
• terminal ganglia
• Vargus node ganglian
Types of Nociecptors - thermal, mechanical & chemical
Thermal - respond to extreme temps
Mechanical- respond to extreme mechanical pressure
Chemical - respond to tissue damage/inflammation
What can activate nociceptors? E.g physical trauma
• chemical
• excessive temperature
• stretching
• ischaemia (insufficient blood flow)
The steps of activating nociceptive neurons?
Detecting nexious stimuli
• chemical, mechanical, thermal
Stimuli is converted into an AP, AP started at site on injury
AP travels to dorsal hom of spinal cord
• here second order neurotransmitters relay information to brain
Brain process this information
Then there is a perception of pain
• cognitive, sensory, emotive
Nociception: Types of fibres -
•A-apha / A-beta
•A-delta
•C-fibres
•A-apha / A-beta ?
• myelinated
• nociception - thermal & mechanical
• mechanical sensitivity
• Speed: very fast
A-delta ?
• myelinated
• nociception - thermal, mechanical & chemical
• mechanical & thermal sensitivity
• Speed: fast
C-fibres ?
• non
• nociception - thermal, mechanical & chemical
• mechanical, thermal & chemical sensitivity
• Speed: slower
Hot plate examples - first pain and second pain?
First pain:
• quick and fast
• signals are carried by myelinated fibres
Second pain:
• slow and delayed
• signals are carried by unmyelinated C fibres
When AP travels to dorsal hom of spinal cord, 2 things can happen ?
• trigger a reflex (hot plate)
• convey info to brain regarding location and intensity
What areas of the brain is affected
• Stomasensory cortex
• limbic system
• prefrontal cortex
Stomasensory cortex - function & linkage to pain perception
Function: sensory aspect
Pain perception: location & intensity of stimulus
Limbic System- function & linkage to pain perception
Function: affective/emotion
Pain perception: emotional aspect of pain
Prefrontal - function & linkage to pain perception
Function: cognitive aspect
Pain perception: behaviour, emotion, memory & decision making
Nociceptors
• Are usually activated by stimuli that can be harmful
• can also be activated by stimuli that can be beneficial e.g. inflammatory response to promote healing
• pain and suffering I’m not the same
Neurotransmitters involved in the descending modulation?
• GABA - BNZ
• serotonin - amitriptyline
• opioid - morphine
• noradrenaline - mythylphenidate
Pain modulation
• Occurs in the spinal level from non-noxious inputs
• occurs in the supraspinal level through the descending modulatory system
Types of pain
Somatic
• pain receptors in muscle, bone, soft tissue
Visceral
Visceral organs
• heart, lungs, pancreas, intestines
Neuropathic
• damage to sensory nerves 
Pain definition?
A unpleasant emotional and sensory experience with tissue damage
Which agent neuropathic pain respond to? 
Anticonvulsants & antidepressant
