Anatomy And Physiology Of Pain Flashcards
What is pain
Pain is an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage
What is the purpose of immediate pain
Immediate pain warns of imminent tissue damage and we should withdraw from the source of the injury
What is the purpose of persisting pain
Persisting pain encourages us to immobilise the injured area so we can give damaged tissue the best chance to heal and recover
What is nociception
The neural processes involved in producing the sensation of pain
What is the nociceptive pathways
The nociceptive pathways is the transduction in the periphery through transmission to the dorsal horn of the spinal horn and then onto the brain
What is acute pain
Pain that lasts for less than 12 weeks in duration
What is chronic pain
Pain that persists for more than 12 weeks
Pain that persists for longer that the tissue healing time
What is nociceptive pain
Pain that arises from the actual or threatened damage to non-neural tissue and is due to the activation of nociceptors
What is neuropathic pain
Pain that is caused by a lesion or disease of the somatosensory nervous system
What is nociplastic pain
Pain that arises from the altered nociception despite no clear evidence of actual of threatened tissue damage causing the activation of peripheral nociceptiors or evidence for disease or lesion of the somatosensory system causing the pain
What are examples of neuropathic pain
Glossopharyngeal neuralgia
Complex regional pain syndrome
Phantom limb pain
Pain due to Spinal cord damage or stroke
What is allodynia
Pain due to a stimulus that does not normally provoke pain
What is dysethesia
An unpleasant abnormal sensation, whether spontaneous or evoked
What is hyperalgesia
Increased pain from a stimulus that normally provokes pain
What is hypoalgesia
Diminished pain in response to a normally painful stimulus
Describe the pain pathway
The peripheral receptors detect the relevant stimulus. The 1st order neuron then takes the signal from the periphery to the ipsilateral spinal cord. The 2nd order neuron which crosses to the contralateral cord, ascends to the thalamus which is a relay station within the brain. The 3rd order neuron then runs from the thalamus to the midbrain and higher cortical centres.
What are nociceptors
They are free nerve endings of primary afferent neurons found in any area of the body which can sense pain eith externally or internally
External examples- skin or cornea
Internal examples- joints, muscles
Where do the cell bodies of the nociceptors reside
Dorsal root ganglia
Trigeminal ganglion
Where are dorsal root ganglion present
On the dorsal root
What is the dorsal root made up of
Composed of cell bodies of nerve fibres that are sensory
What is the spinothalmic tract
This is a sensory pathway that carries pain, temperature and crude touch information from the body
Where does the spinothalmic tract originate
The spinal cord
What does the lateral spinothalmic tract carry
Pain and temperature
What does the anterior spinothalmic tract carry
Crude touch
Where does the spinothalmic tract terminate
It terminates in the thalamus
What sensations does the thalamus not get
The thalamus receives all sensations apart from olfactory
What is the function of the insula
The insula is where the degree of pain is judged
The insula contributes to the subjective aspects of pain perception
It plays a role in perception, motor control, self awareness and interpersonal experience
Play part in the addiction
What is the function of the amygdala
Plays a key role in learned emotional responses such as fear anxiety and depression.
Why is the amygdala important
The amygdala is important for the emotional-affective dimension of pain and for pain modulation
What does hyperactivity in the amygdala account for
Hyperactivity in this brain centre accounts for pain-related emotional responses and anxiety like behaviour
Where is the cingulate cortex located
The medial aspect of the cerebral hemispheres
What is the cingulate cortex linked with
The limbic system
What is the function of the cingulate cortex
Maintains reciprocal connections with other pain processing areas
How can we treat pain
Stimulate descending inhibitory pathway
Gate control
Pharmacotherapy
What is involved in the management of pain
MDT approach
Biological target
Psychology
Physiotherapy
What medications are usually used in pain medicine
NSAID’s
Paracetamol
Opioids
What are opioids good at treating
Acute pain
Eg-after surgery
What are the problems with long term use of opioids
Tolerance
Immunosupression
What are causes of cancer pain
Pain associated with direct tumour
Pain associated with cancer therapy
Pain unrelated to cancer
