Spinal Cord and Tracts Flashcards
the white matter in front of the ventral horn is called what?
ventral funiculus
the white matter lateral on the SC is called what?
lateral funiculus
the white matter in posterior of SC is called what?
dorsal funiculus
why does the white matter increase in size in the SC as you get closer to the brain?
because it has all the tracts whereas if you go down youre losing some
what level of the SC has an enlargement in the gray matter for the sympathetic pregang cell bodies?
T1 to L2
what level of the SC has an enlargement in the gray matter for the parasympathetic pregang cell bodies?
S2-4
where do the pregang cell bodies lay in gray matter in the SC?
lateral horn…aka intermediolateral column
ascending tracts have how many neurons?
3
where is the first nerve cell body in an ascending tract located?
in the dorsal root ganglion
which neuron decusates in ascending tracts?
second neuron
where is the cell body of the third neuron in ascending tracts?
thalamus
where does the third neuron project in ascending tracts?
to the postcentral gyrus
name the two ascending tracts to know
spinothalamic (anterolateral) and dorsal column medial lemniscus
where is the first synapse in the spinothalamic (anterolateral) tract?
at level of sensation in SC
what does the spinothalamic (anterolateral) tract sense? (2)
pain and temperature
where does the spinothalamic (anterolateral) tract decussate? what nerve decussates?
at level of 1st synapse…the second nerve decussates
where does the spinothalamic (anterolateral) tract second synapse occur?
in the VPL of the thalamus
when moving from the VPL of the thalamus to the postcentral gyrus…what does the spinothalamic (anterolateral) tract travel through?
internal capsule
what does the dorsal column medial lemniscus tract sense? (3)
vibration, fine touch, proprioception
where does the first synapse of the dorsal column medial lemniscus tract occur?
in the medial lemniscus of the medulla
where does the dorsal column medial lemniscus tract decussate? what nerve is it?
at medulla level…is second nerve
where does the second nerve in the dorsal column medial lemniscus tract travel from and to?
from the medial lemniscus and to the thalamus (VPL)
where is the second synapse in the dorsal column medial lemniscus tract?
VPL of the thalamus
what does the dorsal column medial lemniscus tract travel in from the VPL of the thalamus to the postcentral gyrus?
internal capsule
what is the name of the tract that the first nerve axon of the dorsal column medial lemniscus tract travels up in the SC?
dorsal column of the SC
what is the name of the tract that the second nerve axon of the spinothalamic tract travels up in the SC?
anterior spinothalamic tract
where is the cell body of the first neuron in the corticospinal tract?
in the precentral gyrus
what is the first neuron called in the corticospinal tract?
upper motor neuron
where do 90% of the upper motor neurons in the corticospinal tract decussate?
in the pyramid of the medulla
where do the other 10% of upper motor neurons in the corticospinal tract decussate?
in the SC at the level they effect
the 10% of neurons in the corticospinal tract that do not decussate in the medulla innervate what tissues? and are called what tract?
innervate the axial skeleton…called the ventral corticospinal tract
the 90% of neurons in the corticospinal tract that do decussate in the medulla innervate what tissues? and are called what tract?
appendicular skeleton innervation and called the lateral corticospinal tract
where is the cell body of neuron 2 in the corticospinal tract?
in the spinal cord ventral horn at the level of innervation
what is the name for the second neuron in the corticspinal tract?
lower motor neuron
what is the hypothalamospinal tract? what info does it convey?
it is a descending tract that conveys sympathetic innervation to the face
what portion of the SC does the hypothalamospinal tract use?
lateral horn
what is unique about the hypothalamospinal tract?
it does not decussate
where is the cell body of the first neuron in the hypothalamospinal tract?
in the hypothalamus
where does the first neuron synapse in the hypothalamospinal tract?
in the thoracic spinal cord in the lateral horn
where is the second neuron cell body in the hypothalamospinal tract?
lateral horn of the thoracic spinal cord
where does the second neuron synapse in the hypothalamospinal tract?
superior cervical ganglion
where does the axon of the third neuron in the hypothalamospinal tract travel from and to?
superior cervical chain to the face
what does the third neuron in the hypothalamospinal tract travel along as it goes to the face?
internal carotid artery
what is the hypothalamospinal tract located next to in the SC?
the lateral corticospinal tract
if there is a lesion in the hypothalamospinal tract what syndrome ensues?
Horners syndrome
name the symptoms of horners syndrome
pupil constriction
eye droop
no sweating
vasodilation (facial flushing)
why do the symptoms of Horners syndrome occur when a lesion happens in the hypothalamospinal tract?
because it conveys sympathetic innervation to the face so the eyes can no constrict or stay open and sweating and vasoconstriction do not happen anymore
what are the two divisions of the dorsal funiculus?
fasciculus cuneatus and fasciculus gracilis
the fasciculus cuneatus includes white matter in the SC from what tract? and what portion of the body?
dorsal column medial lemniscus tract…cervical and thoracic portions so upper limb fine touch, proprioception and vibration
the fasciculus gracilis includes white matter in the SC from what tract? and what portion of the body?
from the dorsal column medial lemniscus tract…lumbar and sacral regions so lower limb fine touch, proprioception and vibration
name the three arteries of the SC
two posterior spinal arteries and one anterior spinal artery
the posterior spinal arteries feed what?
unilateral side of the dorsal funiculus (sensation area)
the anterior spinal artery feeds what?
all of the SC except the dorsal funiculus
