Pain Flashcards
What is the basal ganglia responsible for?
Movement and reward
What is the thalamus?
Sensory gateway
What is the hippocampus responsible for?
Memory
What is the hypothalamus responsible for?
Body function regulation
What is the amygdala responsible for?
Emotion
What are first order neurones?
Dorsal root ganglion mechanosensory neurones
What does is mean when first order sensory neurones are described as pseudounipolar?
They have two axons extending from the cell body and no dendrites
What are the two axons of a mechanosensory neurone called?
Peripheral branch, central branch
What is the unconscious somatosensory ascending pathway?
Proprioception through the spinocerebellar tract
What is the conscious somatosensory ascending pathway?
Nociception and mechanosensation
What is detected by nociception?
Pain and temperature
What is a dermatome?
Neurological mapping of the areas innervated by a spinal nerve
Which layer of the cortex receives thalamic input?
Layer IV
Where does the cortex send information?
To limbic structures and descending
What is the measurement of pain?
Numeric scale of 0 (no pain) to 10 (worst pain)
What is nociception?
The neural process of encoding noxious stimuli
Where can nociceptors be found?
All tissue except the brain
What are the three types of noxious stimuli?
Mechanical, thermal, chemical
What order are pain projection neurones?
Second order
Which receptor detects painful heat?
TRP1V
Which receptor-tricking molecule is found in hot food?
Capsaicin
What are mechanoreceptors?
Stretch-sensitive cation channels
Which nociceptor is polymodal?
Mechano-nociceptor
What are C-fibres?
Polymodal nociceptors responsible for dull aching pain
How is the conscious experience of pain produced?
Integration of pain signals from multiple brain structures
What are discriminative components?
Pathways that target traditional somatosensory areas of the cortex
What are affective-motivational components?
Components that depend on additional cortical and brainstem pathways
Where do 1st order neurones send signals from and to?
Stimulus site -> substantia gelatinosa in dorsal horn
Where do 2nd order neurones send information from and to?
Spinal cord -> thalamus
What information is transported through the lateral spinothalamic tract?
Temperature and pain
What information is transported through the anterior spinothalamic tract?
Crude touch and pressure
Where do 3rd order neurones send information from and to?
Thalamus -> other brain centres
Which nociceptive fibres are responsible for fast sharp pain?
A delta fibres
Which nociceptive fibres are responsible for slow aching pain?
C fibres
What is the ratio of A delta : C nociceptive fibres?
1:9
What are lidocaine and novocaine?
Local anaesthetics
What do anaesthetics do?
Directly inhibit Na+ channels, preventing generation of action potentials
What are nociceptors bathed in and why?
Inflammatory mediators to increase sensitivity and lower depolarisation threshold
What do NSAIDs target?
Production of prostaglandins by COX
What is the first level of nociceptive modulation at the spinal cord?
Substantia gelatinosa segmental controls
What is the purpose of the substantia gelatinosa?
Gating mechanism to modulate incoming signals
What are nociceptive signals integrated in context with?
Other ongoing stimuli
Why does one pain mask another?
Diffuse inhibitory controls by nociceptive stimuli
What makes up the body’s own analgesic system?
Endogenous opioids such as enkephalin
What effect is produced by artificial stimulation of the periaqueductal grey matter?
Analgesic
What are morphine, diamorphine and codeine?
Exogenous opioids used to treat pain
What is referred pain?
Pain perceived at a site other than that of nociception
Where do cutaneous and visceral nociceptive afferents converge?
On projection neurones
What is allodynia?
Pain due to a normally non pain-causing stimulus
What is neuropathic pain?
Pain caused by a lesion or disease of the somatosensory nervous system
