Chapter 15: nervous system pt 2

Question 1

how are the spinal nerves in the cervical spine named

Answer 1

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

Question 2

how are the spinal nerves in the rest of the body (besides cervical) named

Answer 2

• 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

Question 3

where does the spinal cord begin and end?

Answer 3

begins superiorly at foramen magnum and ends at conus medullaris

Question 4

what makes up the foramen magnum?

Answer 4

occipital bone

Question 5

the spinal cord extends down to which vertebral level?

Answer 5

around L1/L2

Question 6

where are spinal taps/epidurals put in? why?

Answer 6

in cauda equine because these nerve fibres are easily moved out of the way when needle is inserted

Question 7

how many segments are found in the cervical spine? thoracic? Lumbar? Sacral?

Answer 7

C = 1-8
T = 1-12
L = 1-5
S = 1-5

Question 8

where is there more white matter in the spinal cord? why?

Answer 8

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)

Question 9

where can you find larger amounts of grey matter in the spinal cord?

Answer 9

larger amount of grey matter in the regions where there’s a lot of outgoing information
-e.g. info exiting to go to limbs

Question 10

which type of cell bodies are found in the dorsal root ganglia?

Answer 10

cell bodies of pseudo unipolar neurons (sensory)

Question 11

what is grey matter made of?

Answer 11

cell bodies and unmyelinated axons

Question 12

what is white matter made of?

Answer 12

myelinated and unmyelinated axons

Question 13

where do spinal nerves exit the spinal cord?

Answer 13

through the intervertebral foramen

• this is where impingement happens when you have a herniated disc for example
• motor and sensory deficits

Question 14

the lateral horn of the grey matter in the spinal cord is only found in which spinal segments?

Answer 14

T1 -T12

-sympathetic trunk ganglia

Question 15

where are the cell bodies of motor neurons found?

Answer 15

anterior horn of the spinal cord

Question 16

what is found in the central canal of the spinal cord?

Answer 16

cerebrospinal fluid

Question 17

what is another name for the cauda equina?

Answer 17

horse’s tail

Question 18

what is the purpose of the filum terminale

Answer 18

• extension off inferior aspect of spinal cord

- combines with other ligaments (coccygeal ligaments) to help adhere spinal cord to inferior aspect of coccyx

Question 19

the film terminale connects to which spinal meningeal layer?

Answer 19

connects to dura mater at inferior aspect of spinal cord

Question 20

dura mater - description

Answer 20

• external meninge
• made of dense irregular CT
• dissipates force in a variety of directions

Question 21

which spinal meningeal layer is in direct contact with the spinal cord?

Answer 21

pia mater

Question 22

where is the epidural space found?

Answer 22

above the dura mater

-this space is filled with adipose tissue to aid with shock absorption

Question 23

where is the subarachnoid space found?

Answer 23

• below the arachnoid mater
• circulates CSF like central canal does
• main function is to protect, circulate nutrients, ions, and waste in NS

Question 24

where is the subdural space found?

Answer 24

-only found in dead bodies

Question 25

how many pairs of spinal nerves do we have?

Answer 25

31

Question 26

what are the CT coverings of the spinal nerves?

Answer 26

• similar to muscles
• epineurium - surrounds entire spinal nerve
• perineurium - surrounds bundles of axons
• endoneurium - surrounds 1 axon

Question 27

collection of cell bodies in the PNS

Answer 27

ganglia

Question 28

collection of cell bodies in the CNS

Answer 28

nuclei

Question 29

______ rami join together in networks to form plexus’

Answer 29

ventral

Question 30

what is the difference between white and grey rami communicans?

Answer 30

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.

Question 31

which spinal segments have both white and grey rami communicans?

Answer 31

T1-L2

Question 32

what are the 5 steps fo a reflex arc?

Answer 32

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