Neuroscience Week 3: Spinal Cord Overview Flashcards
Identify
Identify
Identify
Identify
Posterior horn
The posterior horn, which comprises sensory nuclei.
Intermediate zone
Intermediate zone, which comprises autonomic and spinocerebellar nuclei.
Anterior horn
Anterior horn, which comprises motor nuclei.
The white matter of the spinal cord is segmented into ________ (AKA __________)
- Funiculi
- AKA columns
Posterior Funiculi function
Posterior funiculus carries large proprioceptive sensory afferents for movement and position sensation.
Lateral Funiculus Function
Lateral funiculus carries large motor efferents (ie, the corticospinal tracts).
Anterior Funiculus
Anterior funiculus carries small, thermoceptive and nociceptive sensory afferents for pain and temperature sensation, respectively.
Fasciculus Proprius Function
which comprises the collective bundle of interspinal rostro-caudal white matter projections; thus, it is also referred to as the spinospinal tract.
Referred to as the spinospinal tract
Fasciculus proprius
Identify & Attributes
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.
Lumbosacral cord spinal cord segment attributes
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 spinal cord segment and attributes
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 spinal cord segment and attributes
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.
Luxol Fast Blue stain
Luxol fast blue stain turns the proteolipid of myelin blue, making it prominent.
Posterior Horn Lamina I: the marginal nucleus AKA
posteromarginal nucleus
Posterior Horn Lamina II: substantia gelatinosa
substantia gelatinosa
Posterior Horn Lamina II: substantia gelatinosa named because
so-named because its lack of myelinated fibers gives it a gelatinous appearance on myelin staining.
Posterior Horn Lamina I, II and V similarities
As a simplification, laminae I and II (and also lamina V) receive small, poorly myelinated or unmyelinated fibers, which carry pain and temperature sensation.
Posterior Horn Laminae III and IV comprise
nucleus proprius
Posterior Horn Laminae III and IV
- 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
Posterior Horn Laminae V and VI
They receive descending motor fibers and assist in sensorimotor integration.
Intermediate zone Lamina VII
Comprises the dorsal nucleus of Clarke (a key spinocerebellar nuclear column) and the intermediolateral cell column (a key autonomic nuclear column).
Anterior Horn Laminae VIII and IX
Motor Laminae
Anterior Horn Lamina X
surrounds the central canal
Dorsal Nucleus of Clarke
- Lamina VII in the intermediate zone
- (a key spinocerebellar nuclear column) and the intermediolateral cell column (a key autonomic nuclear column).
*
anterior median fissure
is the deep longitudinal fissure along the anterior surface of the spinal cord.
Leptomeninges
pia/arachnoid mater covering of the spinal cord.
Anterior Spinal Artery
Axon hillock physiology
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.
