Spinal Cord

Question 1

where does the spinal cord run

Answer 1

• from foramen magnum to L1 or L2
• through vertebral canal of vertebral column

Question 2

three functions of spinal cord

Answer 2

• sensory and motor innervation of entire body inferior to head via spinal nerves
• two-way conduction pathway between body and brain
• major centre for reflexes

Question 3

where does spinal cord end at 3rd fetal month

Answer 3

at coccyx

Question 4

where does spinal cord end at birth

Answer 4

at L3

Question 5

where does adult spinal cord extend to

Answer 5

conus medullaris which tapers into causa equina, tethered to coccyx

Question 6

how do spinal cord segments relate to their nerves

Answer 6

spinal cord segments are superior to where their corresponding spinal nerves emerge through intervertebral formina

Question 7

denticulate ligaments

Answer 7

lateral shelves of pia mater anchoring to dura

Question 8

what are the spinal nerves part of

Answer 8

PNS

Question 9

where do spinal nerves lie

Answer 9

in intervertebral foramina

Question 10

how many pairs of spinal nerves are there

Answer 10

31

Question 11

how many pairs of cervical spinal nerve pairs

Answer 11

8

Question 12

how many pairs of thoracic spinal nerve pairs

Answer 12

12

Question 13

how many pairs of lumbar spinal nerve pairs

Answer 13

5

Question 14

how many pairs of sacral spinal nerve pairs

Answer 14

5

Question 15

how many pairs of coccygeal spinal nerve pairs

Answer 15

1

Question 16

what is the cauda equina

Answer 16

a collection of nerve roots at the inferior end of the vertebral canal

Question 17

where do the cervical spinal nerves exit

Answer 17

from above their respective vertebra (eg. nerve root 1 from abov C1, nerve root 2 between C1 and C2)

Question 18

name the three meningeal membranes

Answer 18

• dura mater
• arachnoid mater
• pia mater

Question 19

name the three potential meningeal spaces

Answer 19

• epidural - outside dura
• subdural - between dura and arachnoid
• subarachnoid - deep to arachnoid

Question 20

four functions of CSF

Answer 20

• buffers CNS
• lightens brain
• removes toxic metabolites
• transports hormones

Question 21

three types of protection given to spinal cord

Answer 21

• meninges
• bone
• CSF

Question 22

what is a lumbar puncture also known as

Answer 22

spinal tap

Question 23

how is a lumbar puncture carried out

Answer 23

needle is introduced into subarachnoidal space between L3 and L4 to collect CSF

Question 24

safety consideration for carrying out lumbar puncture

Answer 24

lumbar spine must be flexed so needle can pass between spinal processes (injection into correct space is vital; errors can be lethal)

Question 25

four functions of a lumbar puncture

Answer 25

- collection of CSF and its evaluation to determine infectious and inflammatory diseases affecting the CNS - control of CSF pressure - detection of CSF pressure - anaesthetic delivery

Question 26

what is the dorsal half of H-shaped cross section made up of

Answer 26

cell bodies of interneurons

Question 27

what is the ventral half of H-shaped cross section made up of

Answer 27

cell bodies of motor neurons

Question 28

grey matter pathway

Answer 28

Sensory neurons → cell body → sensory axon → interneuron → cell body (lower motor neurons)

Question 29

what are visceral motor neurons and what do they control

Answer 29

- part of autonomic nervous system - involuntary - control organs

Question 30

what are somatic motor neurons and what do they control

Answer 30

- part of somatic nervous system - voluntary - control skeletal muscle and skin

Question 31

ascending pathways

Answer 31

sensory informaiton by three orders of neurons from body up tp more rostral regions of CNS

Question 32

descending pathways

Answer 32

motor instructions via upper and lower order neurons from brain to more causal regions of CNS

Question 33

two functions of descending pathways

Answer 33

- stimulate contraction of body's muscles - stimulate seceretion from body's glands

Question 34

commissural fibres

Answer 34

white matter fibres crossing from one side of the spinal cord to the other

Question 35

name the three major ascending pathways

Answer 35

- spinocerebellar - dorsal columns - spinothalamic

Question 36

is the spinocerebellar pathway ipsilateral or contralateral

Answer 36

ipsilateral

Question 37

spinocerebellar function

Answer 37

proprioception from skeletal muscles to cerebellum

Question 38

are the dorsal columns ipsilateral or contralateral

Answer 38

contralateral

Question 39

where do the doral columns decussate

Answer 39

medulla

Question 40

dorsal columns function

Answer 40

discriminative tough sensation through thalamus to somatosensory cortex

Question 41

is the spinothalamic pathway ipsilateral or contralateral

Answer 41

contralateral

Question 42

where does the spinothalamic pathway decussate

Answer 42

spinal cord

Question 43

spinothalamic pathway function

Answer 43

nondiscriminate sensations (pain, temp, pressure) through thalamus to the primary somatosensory cortex

Question 44

what do the major descending pathways synapse with

Answer 44

ventral horn interneurons

Question 45

name two pyramidal tracts

Answer 45

- lateral corticospinal - ventral corticospinal

Question 46

where does the lateral corticospinal tract decussate

Answer 46

pyramids of medulla

Question 47

lateral corticospinal tract function

Answer 47

voluntary motor to limb muscles

Question 48

where does the ventral corticospinal tract decussate

Answer 48

spinal cord

Question 49

ventral corticospinal tract function

Answer 49

voluntary to axial muscles