Neuroscience Week 3: Spinal Cord Overview

Question 1

Identify

Answer 1

Question 2

Identify

Answer 2

Question 3

Identify

Answer 3

Question 4

Identify

Answer 4

Question 5

Posterior horn

Answer 5

The posterior horn, which comprises sensory nuclei.

Question 6

Intermediate zone

Answer 6

Intermediate zone, which comprises autonomic and spinocerebellar nuclei.

Question 7

Anterior horn

Answer 7

Anterior horn, which comprises motor nuclei.

Question 8

The white matter of the spinal cord is segmented into ________ (AKA __________)

Answer 8

• Funiculi
• AKA columns

Question 9

Posterior Funiculi function

Answer 9

Posterior funiculus carries large proprioceptive sensory afferents for movement and position sensation.

Question 10

Lateral Funiculus Function

Answer 10

Lateral funiculus carries large motor efferents (ie, the corticospinal tracts).

Question 11

Anterior Funiculus

Answer 11

Anterior funiculus carries small, thermoceptive and nociceptive sensory afferents for pain and temperature sensation, respectively.

Question 12

Fasciculus Proprius Function

Answer 12

which comprises the collective bundle of interspinal rostro-caudal white matter projections; thus, it is also referred to as the spinospinal tract.

Question 13

Referred to as the spinospinal tract

Answer 13

Fasciculus proprius

Question 14

Identify & Attributes

Answer 14

Lumbosacral cord.

• Large gray matter horns, because of the large population of neurons required to innervate the lower limbs.
• Small amount of white matter, because relatively few ascending fibers have joined the cord and relatively few descending fibers remain in it.

Thoracic cord.

• Small gray matter horns, because segmental thoracic innervation requires relatively few neurons.
• Moderately large amount of white matter because of the many fibers relaying to and from the lumbosacral neurons.

Cervical cord.

• Large gray matter horns large because of the large population of neurons required to innervate the upper limbs.
• Large amount of white matter because all descending and ascending fibers either pass through or terminate within it.

Question 15

Lumbosacral cord spinal cord segment attributes

Answer 15

Lumbosacral cord.

Large gray matter horns, because of the large population of neurons required to innervate the lower limbs.

Small amount of white matter, because relatively few ascending fibers have joined the cord and relatively few descending fibers remain in it.

Question 16

Thoracic spinal cord segment and attributes

Answer 16

Thoracic cord

• Small gray matter horns, because segmental thoracic innervation requires relatively few neurons.
• Moderately large amount of white matter because of the many fibers relaying to and from the lumbosacral neurons.

Question 17

Cervical spinal cord segment and attributes

Answer 17

Cervical cord

Large gray matter horns large because of the large population of neurons required to innervate the upper limbs.

Large amount of white matter because all descending and ascending fibers either pass through or terminate within it.

Question 18

Luxol Fast Blue stain

Answer 18

Luxol fast blue stain turns the proteolipid of myelin blue, making it prominent.

Question 19

Posterior Horn Lamina I: the marginal nucleus AKA

Answer 19

posteromarginal nucleus

Question 20

Posterior Horn Lamina II: substantia gelatinosa

Answer 20

substantia gelatinosa

Question 21

Posterior Horn Lamina II: substantia gelatinosa named because

Answer 21

so-named because its lack of myelinated fibers gives it a gelatinous appearance on myelin staining.

Question 22

Posterior Horn Lamina I, II and V similarities

Answer 22

As a simplification, laminae I and II (and also lamina V) receive small, poorly myelinated or unmyelinated fibers, which carry pain and temperature sensation.

Question 23

Posterior Horn Laminae III and IV comprise

Answer 23

nucleus proprius

Question 24

Posterior Horn Laminae III and IV

Answer 24

• They receive large cutaneous sensory fibers — however, that the majority of large fibers do not synapse within the Rexed laminae at all but instead directly ascend the posterior columns.
• comprise nucleus proprius

Question 25

Posterior Horn Laminae V and VI

Answer 25

They receive descending motor fibers and assist in sensorimotor integration.

Question 26

Intermediate zone Lamina VII

Answer 26

Comprises the dorsal nucleus of Clarke (a key spinocerebellar nuclear column) and the intermediolateral cell column (a key autonomic nuclear column).

Question 27

Anterior Horn Laminae VIII and IX

Answer 27

Motor Laminae

Question 28

Anterior Horn Lamina X

Answer 28

surrounds the central canal

Question 29

Dorsal Nucleus of Clarke

Answer 29

• Lamina VII in the intermediate zone
• (a key spinocerebellar nuclear column) and the intermediolateral cell column (a key autonomic nuclear column).
  *

Question 30

anterior median fissure

Answer 30

is the deep longitudinal fissure along the anterior surface of the spinal cord.

Question 31

Leptomeninges

Answer 31

pia/arachnoid mater covering of the spinal cord.

Question 32

Anterior Spinal Artery

Answer 32

Question 33

Axon hillock physiology

Answer 33

Membrane potentials from throughout the cell body spread to the axon hillock, and only if they depolarize it to its threshold will the axon fire an action potential; thus, this is the decision-making center of the neuron.