click below
click below
Normal Size Small Size show me how
Spinal Chords/Nerves
Question | Answer |
---|---|
anatomical segmentation of the spinal cord | C7, T12, L5, S5, starts at foramen magnum, has spinal cord segments with posterior and anterior spinal nerves, and ends at conus medullaris/L2 |
relationship between the spinal cord segments and the vertebral bodies. | pairs of spinal nerves help determine spinal segments, nerves enter through vertebral bodies and protects |
functional significance of the cervical and lumbar cord enlargements | higher number of neurons present |
anatomically speaking, why are the enlargements present | associated with the limbs |
"reflex" | stereotyped response to a given sensory input |
spinal reflex | reflex with circuitry contained within the spinal cord |
spinal nerve - sensory | posterior horn, posterior funiculus, posterior root, PRG is primary afferent |
spinal nerve - motor | anterior horn |
spinal cord reflex arc | receptor, afferent neuron (sensory input) with PRG, interneuron, efferent neuron (autonomic and motor), and target organ (largely skeletal muscle - could also be glads or smooth muscle) |
fiber types for motor axons | anterior |
fiber types for sensory axons | posterior |
What is the functional significance of increasing diameter and myelination? | makes processing faster |
sensory | primary afferent - sensory info into cord, ascending tracts - info to the brain |
efferents | lower motor neurons and autonomics - axons go to the periphery, depending tracks - instructions go to efferents |
integrative | reflexes and program pattern generators |
spinal cord segment | 1 pair of spinal nerves |
spinal nerves | posterior dorsal root, anterior ventral root |
end of cord | conus medullaris |
2 enlargements | cervical (brachial) plexus and lumbar (lumbosacral) plexus |
cervical | upper back and arms |
thoracic | middle torso |
lumbar | butt and legs |
rexed laminae | posterior horn is laminae I-VI (2nd layer is substantial gelatinosa) |