Lecture 12 - Central Nervous System (and some PNS)

Question 1

how does CSF flow from production to reabsorbtion?

Answer 1

FILTRATION SYSTEM
1. CSF is produced by the choroid plexus of each ventricle
2. CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures
3. CSF flows through the subarachnoid space
4. CSF is absorbed into the dural venous sinuses via the arachnoid villi

Question 2

how are the spinal nerves divided up?

Answer 2

• cervical (8)
• thoracic (12)
• lumbar (5)
• sacral (5)
• coccygeal (1)

Question 3

where is the spinal cord located?

Answer 3

• runs from the medulla oblongata to the conus medullaris
• ended between L1 and L2 vertebrae

Question 4

why are there 8 cervical nerves but only 7 vertebrae?

Answer 4

the first cervical spine nerve exits above the first cervical vertebrae, so each subsequent cervical spine nerve exits inferior to a cervical vertebrae

Question 5

what are the enlargements of the spinal cord?

Answer 5

• cervical enlargement
• lumbar enlargement

Question 6

in lower regions of the spine, why aren’t the spinal cords adjacent to their respective vertebrae?

Answer 6

• the spinal cord grows slower than the vertebral column during development
• this is most pronounced in the lumbar and sacral regions

Question 7

what is the conus medularis?

Answer 7

• the area in which the spinal cord ends
• vertebrae L1 or L2

Question 8

what is a lumbar puncture?

Answer 8

• a spinal tap
• usually performed in L3 area to remove CSF because spinal cord doesn’t usually run that far inferiorly

Question 9

what are the functional differences between the parasympathetic and sympathetic nervous system?

Answer 9

1.) origination: parasympathetic = brain stem or sacral spinal cord, sympathetic = thoracic and lumbar spinal cord
2.) preganglionic fibers: parasympathetic = long, sympathetic = short
3.) postganglionic fibers: parasympathetic = short, sympathetic = long
4.) location of ganglia: parasympathetic = near visceral effector organs, sympathetic = close to spinal cord