12 - Pain Pathway Flashcards
Where does the pain pathway crossover?
at spinal cord
Are pain and temperature innervated by different receptors/specialised afferents etc?
How can you record this experimentally?
What does the graph of afferent nociceptor and thermoreceptor response look like as temp increases to 50+ degrees?
-yes there are noiciceptors and thermoreceptors
-by recording noiciceptor and thermoreceptor response from 0 to 50 degrees temperature
-thermoreceptors: sharp initial increase
noiciceptors: increase only at 45+ degrees
Which type of nerve fiber innervates the first pain?
A delta fiber
What is capsaicin?
What receptor does it bind to?
How does the binding of capsaicin compare to other activators?
-chemical found in chilli peppers
-vanilloid receptor on TRPV1 channel
-capsaisin binds to intracellular and H+, heat binds to extracellular
Does cervical or lumbar innervate the lower body somatosensation?
lumbar lower body
Why is TRPV1 classed as a polymodal receptor channel?
What cations pass thru this channel?
-because it is activated by multiple: heat, pH and capsaicin
-calcium, potassium
Where does the spinothalamic end up?
How does it compare to DCLS and trigeminal pathway?
both end up in primary somatosensory cortex
Why does a lesion in the left half of the spinal cord result in reduced sensation of temp./pain on the left side of body and reduced sensation in two-point discrimination, vibration and proprioception?
because the temp./pain spinothalamic pathways crosses from the left anterolateral column over the right side of body.
Whereas mechanoreceptive system DCLS stays on the left
Uniquely, where does the visceral pain pathway cross over?
medulla
Where do the major pathways for discriminative aspects of pain and temperature sensation cross over?
medulla
Where do affective-motivational pain pathways cross over?
cervical/lumbar spinal cord
