spinal cord

Question 1

spinal cord

Answer 1

ends between L1-L2 of the vertebral column in adults and L4 in infants
terminates at conus medullaris
anchored to coccyx by the film terminale
divided into 5 regions and 31 segments

Question 2

spinal nerves

Answer 2

branch to form peripheral nerves that innervate all part of the body
mixed nerves= contains axons of sensory and motor neurons
connect to spinal cord by dorsal and ventral nerve root

Question 3

dorsal root

Answer 3

contains axons of sensory neuron

dorsal root ganglion contains cell bodies of sensory neuron

Question 4

ventral root

Answer 4

contains the axons of motor neuron

Question 5

cauda equina

Answer 5

lumbar, sacral and coccygeal nerve roots travel beyond conus medullaris to reach the vertebral region from which those spinal nerves emerge

Question 6

protection of spinal cord

Answer 6

vertebral column
cerebrospinal fluid
spinal meninges

Question 7

spinal meninges

Answer 7

extend beyond spinal cord to second sacral vertebra
lumbar puncture involves insertion of needle into subarachnoid space beyond L3= doesn’t damage spinal cord, withdraw CSF fluid for diagnostic testing
outer dura mater is separated from vertebral column by epidural space

Question 8

internal anatomy of spinal cord

Answer 8

neural tissue of spinal cord divided into left and right side by 2 grooves:
anterior median fissure
posterior median sulcus

Question 9

gray matter

Answer 9

neuron cell bodies, unmyelinated axons & neuroglia
gray commissure= site where axons cross from one side of the CNS to the other
subdivided into gray horns which contain sensory or motor nuclei

Question 10

sensory nuclei of posterior gray horns

Answer 10

contain the cell bodies of spinal cord interneurons which receive and process incoming sensory input

Question 11

somatic motor nuclei of anterior gray horn

Answer 11

contains the cell bodies of lower motor neuron

Question 12

autonomic motor nuclei of lateral gray horns

Answer 12

contain the cell bodies of preganglionic neuron

Question 13

white matter

Answer 13

composed of myelinated & unmyelinated axons

anterior white commissure = site where axons cross from one side of the CNS to the other

Question 14

spinal cord tracts of the white matter

Answer 14

ascending tracts= conduct sensory input to brain

descending tracts= conduct motor input away from the brain

Question 15

somatosensory pathway

Answer 15

general sensory input

involves 1st, 2nd, 3rd order neuron

Question 16

3 main somatosensory pathway

Answer 16

spinothalamic, posterior column pathway and spinocerebellar

Question 17

spinothalamcic pathway

Answer 17

conducts sensation of crude touch, deep pressure, pain and temp

Question 18

first order neuron

Answer 18

1st order conduct sensory input from receptors into posterior gray horn synapse with 2nd within a sensory nucleus

Question 19

2nd order neuron

Answer 19

2nd order conduct sensory input to thalamus ascend spinal cord in a:
anterior spinothalamic tract (crude touch & deep pressure)
lateral spinothalamic tract (pain & temperature)
synapse with 3rd order in the thalamus

Question 20

3rd order neuron

Answer 20

conduct sensory input to the primary somatosensory cortex

Question 21

posterior column pathway

Answer 21

conducts sensation of fine touch, light pressure, vibration and proprioceptors

Question 22

1st order neuron

Answer 22

conduct sensory input into posterior gray horn and to the medulla oblongata ascends spinal cord in a fascuclus gracilis or fascuclus cuneatus
synapse with 2nd order in the medulla oblongata

Question 23

2nd order neuron

Answer 23

conducts sensory input to the thalamus

synapse with 3rd order in the thalamus

Question 24

3rd order neuron

Answer 24

conducts sensory input to the PSC

Question 25

spinocerebellar pathway

Answer 25

conducts sensation of proprioceptors

Question 26

1st order neuron

Answer 26

conduct sensory input from proprioceptors into a posterior gray horn
synapse with 2nd order with sensory neuron

Question 27

2nd order neuron

Answer 27

conduct sensory input to the cerebellum

ascend spinal cord in an anterior/ posterior spinocerebellar tract

Question 28

somatic motor pathway

Answer 28

conduct somatic motor output from primary motor cortex to skeletal
involve a relay of 2 neuron
involve upper and lower motor neuron
2 main somatic motor pathways: later and anterior corticospinal pathway

Question 29

lateral corticospinal pathway

Answer 29

conducts somatic motor output that controls skeletal muscles of limbs

Question 30

upper motor neuron

Answer 30

conduct somatic motor output from the PMC to an anterior gray horn
descend spinal cord in a lateral corticospinal tract
synapse with lower motor neuron in a motor nucleus

Question 31

lower motor neuron

Answer 31

conduct somatic motor output to skeletal muscles of the limbs

Question 32

anterior corticospinal pathway

Answer 32

conducts somatic motor output that controls the skeletal muscle of the axial skeleton

Question 33

upper motor neuron

Answer 33

conduct somatic motor output from the PMC to an anterior gray horn
descend the spinal cord in an anterior corticospinal tract
synapse with lower motor 1 in a motor nucleus

Question 34

lower motor neuron

Answer 34

conduct somatic motor output to skeletal muscle of the axial skeleton

Question 35

somatic reflex

Answer 35

mediated by reface integration centres within the spinal cord
stimulate skeletal muscle contractions
involve LMN
conduct motor output from spinal cord to skeletal muscle
can be modified by the PMC
motor output conducted to the reflex integrations centres of the spinal cord via UMN within the corticospinal tracts
can be used to quickly diagnose disorders of nervous systems= spinal cord segment
lower motor neuron
primary motor cortex
corticospinal tracts

Question 36

common somatic reflexes

Answer 36

patellar
biceps
triceps
plantar

Question 37

spinal cord injures

Answer 37

damage to posterior gray horn or ascending spinal cord tracts= of sensation
damage to anterior gray horn or corticospinal tracts= spastic or flaccid paralysis
damage upper= spastic paralysis
damage to lower= flaccid