Pain Flashcards
What is pain?
An unpleasant sensory and emotional experience associated with damage
What factors can affect someone’s pain?
Medication, past experience, movement, gratitude and surroundings
What do nociceptors sense?
Pain
Describe the location of pain receptors in human body?
External and internal
What different causes of tissue damage result in pain?
Burns, ischaemia, infection and inflammation
What are the two types of pain?
Acute and chronic
What is the pain pathway?
1) Pain stimulus
2) Nociceptor
3) Transmission to spinal cord via sensory neurones
4) spinal cord processing
5) transmission of pain via ascending tracts in spinal cord to brain
6) processing of pain info in the brain
What are the 2 stimulus for pain?
Physical or chemical
Give an example of a physical stimuli?
Burn
What are the 2 types of nociceptor?
1) High threshold mechanical receptors
2) polymodal nociceptors
Which nociceptor responds to intense mechanical stimulation?
High threshold mechanical receptor
What are the four basic processes of pain?
1) transduction
2) transmission
3) perception
4) modulation
Mast cells release what when in pain?
Histamines
The release of histamines, stimulate the release of what neurochemicals?
Substance P
What is ischaemia?
A shortage of blood
What is hypoxia?
Lack of oxygen
Why does ischaemia and hypoxia cause pain?
Blood flow interruption leads to a mass of pain stimulating chemicals
What are the two types of afferent or sensory neurones which conduct the pain impulses to the spinal cord?
A delta fibres and c fibres
Describe the A delta (first pain) fibre?
An early, localised, intense pain which also mediates the sensation of itching
Describe a C fibre? (Second pain)
A slow conducting fibre, a late, poorly localised, long lasting, dull pain
What does the transmission process consist of?
The pain is transmitted:
1) site of transduction > nociceptor fibres > dorsal horn in spinal cord
2) spinal cord > brain stem
3) connections between thalamus > cortex and higher levels of the brain
Why do A delta fibres transmit pain impulses more quickly than C fibres?
They send impulses faster
The grey matter in the spinal cord is organised into a number of layers of?
Laminae (thin layers)
The spinal cord consists of what colour matters?
Grey - cells and primary afferent from the periphery
White - ascending and descending fibres
Layer 1 of the dorsal horn is called “Lamina I”. Layer 2 is called?
Lamina II
What is Central sensitisation?
Neurones in the spinal cord become more sensitive
What is the most important spinal cord pathway for signalling pain stimuli?
Lateral spinothalamic tract pathway
What is the first neurones involved in the spinothalamic tract? (Pathway from skin to the thalamus)
A or C fibres (Skin)
The end result of neuronal activity is?
The perception of pain
What is reticular formation ?
Network of pathways in the brainstem connecting the spinal cord, cerebrum and cerebellum. Maintaining consciousness
What autonomic responses can be observed when someone is suffering pain?
Fight or flight, muscles tighten, breathing rapid/shallow, HR increase, BP increase, cold and clammy, pupils dilate
What does the anterior cingulate cortex do in the brain in relation to pain?
Integrates information about pain perception and can remember how it happened to avoid in the future
What are the 3 perceptions of pain?
1) sensory
2) motivational
3) cognitive
What is the descending modulatory pain pathway (DMPP)?
The multiple, complex pathways involved in the modulation of pain
What is analgesia?
Can’t feel pain
Name some inhibition neurotransmitters involve with the modulation of pain?
Serotonin, GABA, noradrenalin, neurotensin and endogenous opioids (endorphins)
Which type of stimuli would you associate with pain from all types of tissue damage?
Chemical
High threshold mechanoreceptors respond to?
Intense mechanical stimulation
In response to a pain stimulus, mast cells secrete?
Histamine
The ‘neurochemical soup’ which occurs as a result of painful stimuli activates the nociceptor, causing the opening of?
Sodium channels
First pain is associated with high threshold mechanoreceptors and A delta fibres. This type of pain is often described as?
Sharp
