Lecture 3-spinal cord pt 3 Flashcards Preview

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Flashcards in Lecture 3-spinal cord pt 3 Deck (51)
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what does gray matter contain
what does white matter contain

-cell bodies and their dendritic processes and synaptic connections
-myelinated fibers/axons going longitudinally


what is a tract/fasciculus

collectoin of axons w/ a common origin, course, and termination


what is a funiculus/column

2 or more fasciculi


what does the dorsal funiculus contain?

fasciculus gracilis (all lvls)
fasciculus cuneatus (C1-T6)


what do the ventral funiculus contain?

the ventral white commissure


where is the dorsal intermediate sulcus found

midthoracic segments and above (C1-T6)
-notably absent in lumbar regions, only found where there is fasiculus cuneatus


which fissure/sulci is very deep?

ventral median fissure unlike the dorsal median sulcus


what receives dorsal roots white

dorsal lateral


where do ventral roots emerge white

ventral lateral


what does the dorsal horn gray contain



what does the ventral horn gray contain

motor nuclei


waht does the lateral horn gray contain? where is it present at?

autonomic motor
only present w/ symp pre gang cell body (T1-L3 only)


what is the substantia gelatinosa homologous to?

spinal trigeminal nucleus


where is clarke's nucleus found?



what information does substantia gelatinosa carry?

senosry in function, temperature
substance P
these are nuclei


where is clarke's nucleus prominent at

lower thoracic levels


where is clarke's nucleus located? why is it located there?

dorsal horn gray bc of its function in sensory prcoessing


waht does substance P act liek a cap to

dorsal horn


what does the ventral horn contain

cell bodies for lower motor neurons and found at all levels of the cord


what are the two types of lower motor neurons

alpha motor neurons: innervate extrafusal striated skeletal muscle fibers ("do work" when lifting)

gamma motor neuron: innervate intrafusal muscle fibers of muscle spinkles (keeps muscle spindle receptor sensitive to new changes in lenght)


what happens when alpha motor neurons are lesioned

cant contract skeletal muscle which leads to paralysis


why do alpha motor neurons have enormous cell bodies and dendritic trees?

bc everyone wants to influence them. there are lots of descending tracts and reflex pathways that will want to synapse on them in order to influence their final decision as to whether to "fire" to contract msucle


how do alpha motor neurons leave the ventral horn gray? what do they eventually merge w/ and innervate?

via ventral roots and will eventually merge into the spinal nerve and go out to the periphery to innervate skeletal muscle


what do alpha motor neurons that are located more medially tend to innervate

axial muscles or ones that are considered proximal like shoulder and arm


in the chunk of ventral horn that is located more lateral, what do those alpha motor neurons tend to innervate/

the appendicular or distal muscles like the forearm and hand (limbs)


where are flexor motor neurons located at in the ventral horn ?
where are extensor motor neurons located in the ventral horn?

more dorsally in the ventral horn

more ventral in the ventral horn


where is the intermediolateral cell column found
what do they contain

lateral horns
preganglionic sympathetic fibers


where does the oculosympathetics originate from? and wehre at

the ciliospinal center of budge at C8-T2


how are the cervical regions shaped? and why?

oval shaped and contain the largest absolute amount of white matter.
-all of the descending tracts, destined for cervial, thoracic, lumbar, and sacral have to go through the cervical region
-sensory ascending tracts starting in the sacral region go up, from lumbar and adding on thoracic, adding on cervical, etc.
SO...dorsal columns are more fully present at the cervical levls


why is the cord enlarged in the lower cervical and lumbosacral regions

to accommodate innervation of the arms and legs