pain

Question 1

the somatosensory cortex (where sensation (including pain) is perceived) is anterior/posterior to the central sulcus?

Answer 1

posterior

Question 2

1st order neuron senses pain (from prostaglandin and cytokine release) and goes via which tract towards the spinal cord

Answer 2

dorsal horn, where it synapses with a second order neuron
(the dorsal root ganglion is where the cell body is, not where the synapse is)

Question 3

in the pain pathway, what does the second order neuron do after starting in the dorsal root ganglion

Answer 3

decussates to the contralateral side of the spinal cord and then goes up the spinothalamic tract
terminates in the thalamus

Question 4

where does the 3rd order neuron go to after synapsing with the 2nd order neuron coming up the spinothalamic tract?

Answer 4

from thalamus to the somatosensory cortex region which correlates to the part of the body that is in pain

Question 5

what is substance P

Answer 5

undecapeptide (11 amino acids)
a type of tachykinin
released by 1st order neuron in the synapse to the 2nd order neuron in the perception of pain

Question 6

what role does the 5HT/NA neuron from the nucleus raphe in the medulla (descending pain pathway) play?

Answer 6

it intervenes at the synapse between the 1st and 2nd order neurone of the ASCENDING pain pathway, to control/inhibit the pain signal

ALSO

stimulates an interneuron to release endogenous opioids

Question 7

what does the interneuron in the substantia gelatinosa do?

Answer 7

helps to inhibit the ascending pathway of pain by releasing endogenous opioid (encephalin) and inhibit the 1st order ascending pain pathway neuron from releasing substance p, and inhibit the depolarisation of the 2nd order ascending pain pathway neuron