Key concepts: Spinal pathways

Question 1

conditions

Answer 1

stroke
trauma

Question 2

somatosensation

Answer 2

sensations from the body
picked up by cutaneous receptors in the skin
different types depending on touch type

Question 3

what is the dorsal column medial leminiscus pathway involved in

Answer 3

proprioception and fine touch

Question 4

dorsal column medial leminiscus pathway

Answer 4

cutaneous receptors/proprioceptors
dorsal roots in the spinal cord
medulla via the fasciculus gracilis (lower half) or the fasciculus cuneatus (upper half)
synapse in the nucleus gracilis/cuneatus
medial leminiscus leaves dorsal column nuclei
decussates before travelling to the thalamus
synapses in the ventral posterolateral nucleus in the thalamus
post central gyrus (containing somatosensory cortex)
where somatotopic arrangement occurs

Question 5

pain and the anterolateral system

Answer 5

pain is detect by nociceptors
cutaneous receptors detecting pain and very hot temperatures

Question 6

3 tracts involved in the anterolateral system

Answer 6

spinothalamic
spinoreticular
spinomesencephalic

Question 7

spinothalamic pathway

Answer 7

considered the main pathway
recognition of pain location

nociceptors to the spinal cord
synapse in the spinal cord
decussate in the spinal cord
travel up the spinal cord to the ventral posterolateral nucleus
synapse
another neuron travels to somatosensory Cortex

Question 8

spinoreticular pathway

Answer 8

not clearly defined
related to changes in attention levels after pain
same pathway as spinothalamic
also project to reticular formation= neuronal network for wide range of functions such as attention and consciousness

Question 9

spinomesencephalic pathway

Answer 9

control and inhibition of pain
same as the spinothalamic
but they synapse in the periaqueductal grey in the midbrain and can activate natural pain suppression system involving opioid release= painkilling effect
release of endogenous opioids and other neurotransmitters= inhibition of pain in the spinal cord and naturally produced analgesia

Question 10

what is the corticospinal tract

Answer 10

movement related information form motor cortex to the spinal cord
neurons are called upper motor neurons: form connections with lower motor neurons carrying muscle related impulses to muscles to contract

Question 11

corticospinal tract pathway

Answer 11

upper motor neurons leave motor cortex and descend to the brainstem
to the cerebral peduncles in the midbrain
tract continues down into the medulla where fibers form 2 bundles known as the pyramids
at the base of the pyramids 90% of fibers decussate in the bundle called the decussation of the pyramids
ifbers enter the spinal cord on opposite side of the body where they originated as part of the lateral tract
10% continue on the same side where they originated in the ventral tract
cross over when they reach the level of the spinal cord where they’ll synapse on a Lower motor neuron

Question 12

lateral corticospinal tract

Answer 12

controls movement of more distal muscles

Question 13

anterior corticospinal tract

Answer 13

movement of more proximal muscles