Lect 2 Spinal Cord

Question 1

Afferent (sensory nerve) fibers

Answer 1

carry information from sensory receptors in skin to CNS

synapse in Posterior Horn

Question 2

Efferent (motor) nerve fibers

Answer 2

carry information from the CNS to the periphery (eg. innervate skeletal muscles)
leave from Anterior horn

Question 3

Afferent & Efferent Nerve

Answer 3

they are different fibers but run within the same nerve, can be thousands of axons within a nerve

Question 4

spinal rootlets

Answer 4

thin bundles of afferent and efferent fibers/axons

Question 5

spinal root

Answer 5

formed by groups of rootlets that converge 
dorsal root (sensory)
ventral root (motor)

Question 6

spinal nerve

Answer 6

formed by union of dorsal root and ventral root

Question 7

spinal segment

Answer 7

the region between two groups of rootlets

Question 8

order of spine components converging

Answer 8

rootlets-> spinal root -> spinal nerve -> spinal segment

Question 9

Spinal cord

Answer 9

part of CNS
31 pairs of spinal nerves that emerge from spinal cord are part of the PNS
rostral spinal cord is continuous with brainstem
Technically ends at L1 vertebral level, but extends with vertebral bodies

Question 10

Pairs of spinal nerves

Answer 10

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 11

brainstem

Answer 11

part of CNS

Cranial nerves III - XII emerge from brainstem and are part of PNS

Question 12

conus medullaris

Answer 12

levels L1-L2

bony vertebral level where spinal cord ends

Question 13

cauda equina

Answer 13

below conus medullaris

collection of nerve roots that course inferiorly to reach its corresponding intervertebral foramen

Question 14

best place for a spinal tap

Answer 14

below the conus medullaris

Question 15

filum terminale

Answer 15

extension of the pia mater

anchors the spinal cord caudally to coccyx

Question 16

myelin stain of spinal cord

Answer 16

gray matter: unstained

White matter: stained

Question 17

nissl stain

Answer 17

gray matter: stain

white matter: unstained

Question 18

Spinal Cord white matter components

Answer 18

Dorsla Funiculus
Lateral funiculus
Ventral Funiculus

all further subdivided into fasiculi and tracts

Question 19

Propriospinal fibers

Answer 19

confined to the spinal cord, begin and end
are predominantly located at the margins of gray matter (surround interior aspects of the funiculi)
allow for communication bw neurons at the same and distant spinal cord levels and are thought to be important in reflex circuitry

Question 20

Gray matter of spinal cord

Answer 20

4 areas
Dorsal horn 
intermediate zone
ventral horn
area around central canal

These further subdivide into laminae, demarcations of laminae are based on size and shape of neurons, their inputs and projections

Question 21

dorsal horn laminae

Answer 21

1-4

Question 22

intermediate zone laminae

Answer 22

7

Question 23

ventral horn laminae

Answer 23

8-9

Question 24

area around central canal laminae

Answer 24

10

Question 25

Spinal cord segments white matter pattern

Answer 25

Amount of white matter decreases rostral to caudal

Question 26

Grey matter of spinal cord

Answer 26

cervical enlargement - C5-T1
lumbar enlargement - L2-S3
location of anterior horn cell bodies- motor to upper extremities and lower extremities

Question 27

cervical and lumbar enlargements

Answer 27

formed by increased numbers of anterior horn cells

neurons project their axons to muscles of UE & LE

Question 28

T1 to L3

Answer 28

Lateral horn/ intermediolateral cell column is also gray matter, this is the site of preganglionic sympathetic neuronal cell bodies

Question 29

lateral horn

Answer 29

site of preganglionic sympathetic neuronal cell bodies