Anatomy

Cervical Region
Thoracic Region
Lumbar Region
Sacral Region
Cervical and Lumbar Enlargements
Gray vs White Matter divisions
Gray Commissure
Dorsal and Ventral and Lateral Horns
Anterior and Posterior Fissures
Spinal Nerves
Roots
Rootlets dorsal root ganglion

Spinal Cord

Function - conduction, locomotion, reflexes
Anatomy
only extends to L1 31 pairs from cervical (8),
thoracic (12), lumbar (5), and sacral (5), coccygeal (1)

Ascending Tracts (2nd - 3rd neuron) - It synapses with interneuron to
thalamus OR is white matter of interneuron that synapsed with sensory neuron.

Dorsal column pathways
deep touch, visceral pain, proprioception fasciculus
gracilis & cuneatus - tracts from LEGS & ARMS
respectively Decussation occurs in medulla for this sensory
tract ONLY
Spinothalamic tract
pain, pressure, temperature, light touch, tickles, itch
Spino cerebellar
proprioception from limbs & trunk to cerebullum

Descending tracts (1st order neuron) - synapses with lower motor
neurons in ventral horn.

Corticospinal Tract - precise, coordinated limb movements
Extrapyramidial System - brain stem, motor nuclei, motor pathways,
NOT part of pyramidal system
tectospinal tract - reflex turning head to sight and
sounds reticulospinal tract - limb movements maintain
postures & balance vestibulospinal tract - postural
activity based on inner ear signals

Decussation

Sensory Neurons
occur in spinal cord crossing of interneuron from one
side to the other (contraction) ascending tract therefore
on opposite side from dorsal root ganglion the impulse entered
through occurs at level of spinal nerve entry therefore
occurs at each level
Motor Neurons
occurs in medulla oblongata projection fibers of
descending tract from cortex crosses so cortex of one hemisphere
controls opposing side of the body

Pathologies

Spina Bifida - failed fusion of vertebra round ___ tube, congenital
Poliomyelitis (polio virus) - weakness --> paralysis --.
respiratory arrest
Polio Virus Symptoms and Cause and Target: Lower Motor
Neurons
Amyothrophic Lateral Sclerosis (ALS)- Lou Gehrigs - sclerosis of
spinal cord due to glutamate toxicity , paralysis & muscle atrophy
ALS Symptoms and Cause and Target: Lower Motor neurons &
pyramidal tract