Chapter 15: nervous system pt 2 Flashcards
how are the spinal nerves in the cervical spine named
the number of the spinal nerve corresponds to the cervical spinal segment below the nerve
-e.g. the spinal nerve exiting between C3 and C4 is spinal nerve C4
how are the spinal nerves in the rest of the body (besides cervical) named
- opposite of spinal nerves exiting from cervical spine
- spinal nerve named after segment above
- e.g. spinal nerve exiting between T4 and T5 is spinal nerve T4
where does the spinal cord begin and end?
begins superiorly at foramen magnum and ends at conus medullaris
what makes up the foramen magnum?
occipital bone
the spinal cord extends down to which vertebral level?
around L1/L2
where are spinal taps/epidurals put in? why?
in cauda equine because these nerve fibres are easily moved out of the way when needle is inserted
how many segments are found in the cervical spine? thoracic? Lumbar? Sacral?
C = 1-8 T = 1-12 L = 1-5 S = 1-5
where is there more white matter in the spinal cord? why?
more white matter the higher you are in the spinal cord
-this is because the anterior portions of the spinal cord must carry all the tracts of everything below. the further you get down the cord, the less tracts there are left (don’t need as much structural support from myelin)
where can you find larger amounts of grey matter in the spinal cord?
larger amount of grey matter in the regions where there’s a lot of outgoing information
-e.g. info exiting to go to limbs
which type of cell bodies are found in the dorsal root ganglia?
cell bodies of pseudo unipolar neurons (sensory)
what is grey matter made of?
cell bodies and unmyelinated axons
what is white matter made of?
myelinated and unmyelinated axons
where do spinal nerves exit the spinal cord?
through the intervertebral foramen
- this is where impingement happens when you have a herniated disc for example
- motor and sensory deficits
the lateral horn of the grey matter in the spinal cord is only found in which spinal segments?
T1 -T12
-sympathetic trunk ganglia
where are the cell bodies of motor neurons found?
anterior horn of the spinal cord
what is found in the central canal of the spinal cord?
cerebrospinal fluid
what is another name for the cauda equina?
horse’s tail
what is the purpose of the filum terminale
- extension off inferior aspect of spinal cord
- combines with other ligaments (coccygeal ligaments) to help adhere spinal cord to inferior aspect of coccyx
the film terminale connects to which spinal meningeal layer?
connects to dura mater at inferior aspect of spinal cord
dura mater - description
- external meninge
- made of dense irregular CT
- dissipates force in a variety of directions
which spinal meningeal layer is in direct contact with the spinal cord?
pia mater
where is the epidural space found?
above the dura mater
-this space is filled with adipose tissue to aid with shock absorption
where is the subarachnoid space found?
- below the arachnoid mater
- circulates CSF like central canal does
- main function is to protect, circulate nutrients, ions, and waste in NS
where is the subdural space found?
-only found in dead bodies
how many pairs of spinal nerves do we have?
31
what are the CT coverings of the spinal nerves?
- similar to muscles
- epineurium - surrounds entire spinal nerve
- perineurium - surrounds bundles of axons
- endoneurium - surrounds 1 axon
collection of cell bodies in the PNS
ganglia
collection of cell bodies in the CNS
nuclei
______ rami join together in networks to form plexus’
ventral
what is the difference between white and grey rami communicans?
White rami communicans: carry preganglionic sympathetic fibers from the spinal nerves to the sympathetic ganglia.
Gray rami communicans: carry postganglionic sympathetic fibers from the sympathetic ganglia to the spinal nerves.
which spinal segments have both white and grey rami communicans?
T1-L2
what are the 5 steps fo a reflex arc?
1) stimulation and activation of receptor
2) activation of a sensory neuron
3) information processign in CNS
4) activation of a motor neurone
5) response by effector
