Spinal Pathways I and II Flashcards
where the spinal cord ends at birth; where it ends in adults
L3//L1-L2 interspace due to the vertebral column maturing after the spinal cord.
what causes the spinal roots below L3 that form the cauda equina?
differential growth of the spinal cord and vertebral column
the space where the blood vessels enter and exit the spinal cord
the perivascular space (extension of subarachnoid)
space filled with CSF
subarachnoid space
what forms the external glial membrane on the surface of the CNS?
astrocytes and their processes
the internal glial membrane exists between the..
parenchyma of spinal cord and ependymal cells that line the ventricles and central canal (these cells are part of the limiting membrane between the CSF and brain.)
vertebral levels of the cervical enlargement; vertebral levels of the lumbosacral enlargements, and what they form
C5-T1 (forms brachial plexus); L3-S1 (forms lumbosacral plexus)
the funiculi of white matter, and where they’re located
posterior funiculus (dorsal column)- between the posterior median septum and the dorsal root fibers lateral funiculus- between the dorsal and ventral roots anterior funiculus (ventral funiculus)- between the ventral roots and the anterior median fissure
describe the location of fasciculus gracilis and fasciculus cuneatus
gracilis is posteromedial, cuneatus is posterolateral
where is Lissauer’s tract?
immediately dorsal to the apex of the dorsal horn
lamina II is the
substantia gelatinosa
lamina VIII is called the..//function?
commissural nucleus (many of its neurons project to the opposite side through the ant. commissure)
dorsal nucleus (Clarke’s/nucleus dorsalis) is only present..
levels T1-L2/L3
the sacral autonomic nucleus’s cells give rise to..
preganglionic autonomic fibers to parasympathetic ganglia
the intermediolateral nucleus cells give rise to..
preganglionic autonomic fibers to the sympathetic ganglia
which lamina contains the motor neurons to skeletal musculature?
lamina IX
what are tract cells?
have axons which enter the white matter and ascend into the brain stem
what is the function of commissural neurons?
axons cross to the opposite side of the spinal cord in the anterior white commissure
what is the fasciculus proprius (propriospinal tract)?
axons ascend or descend in the white matter and synapse somewhere along the spinal cord
a peripheral afferent fiber having its origin in a DRG cell
primary neuron
tracts are usually composed of what type of neuron?
secondary (or tertiary)
what sensory modalities does the dorsal column- medial lemniscus pathway carry?
two point touch, pressure, vibration, and joint position, to the cerebral cortex
if the afferent fiber enters below the T6 level, it joins…./if it enters above the T6 level it joins…
fasciculus gracilis; fasciculus cuneatus.
in this ascending pathway, the secondary neuron is located..
in the caudal medulla
secondary fibers from the dorsal column nuclei decussate to the opposite side of the medulla as..
internal arcuate fibers
internal arcuate fibers coalesce to form the
medial lemniscus (flat band of fibers, which synapse on third order neurons in the ventral posteriorlateral nucleus of the thalamus)