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The spinal chord extends from the foramen magnum to the....
2nd lumbar vertebrae
What is contained in the Internal anatomy of the spinal chord?
- Anterior & Posterior Median
- Gray Matter
- Gray Commissure
- Central Canal
- Anterior White Commissure
- Anterior & Posterior Gray Horns
- Lateral Gray Horns
- Posterior Root Ganglion
- Spinal nerve
- Cauda equina
What are the Regions of White Matter?
- Anterior White columns
- Posterior white Columns
- Lateral White Columns
- All Columns contain sensory(ascending) and
- motor(descending) tracts that extend long distances up or down the spinal chord
What is located in the anterior, posterior, lateral Gray horns and white columns?
Anterior Gray Horns-contain cell bodies of somatic motor neurons that provide impulses for skeletal muscle contractions
Posterior Gray Horns-contains interneurons as well as axons of incoming sensory neurons
Lateral Horns-are between posterior and anterior gray horns, contain cell bodies of autonomic motor neurons that regulate the activity of cardiac muscle, smooth muscle and glands
White Columns-contain sensory and motor tracts that may extend long distances up or down the spinal chord
Compare ascending and descending spinal tracts
- Ascending(sensory)-propagate up the spinal chord to the brain along two main routes on each side(spinothalamic tract and posterior column)
- spinothalamic tract-conveys impulses for sensing pain, itchiness and deep pressure
- Posterior tract- convey impulses for discriminating touch, light pressure and deep pressure.
- Descending(motor)-motor output to skeletal muscles travel down the spinal chord in two types of pathways(direct and indirect)
- Direct-convey impulses that originate in the cerebral cortex and are destined to cause voluntary movements of skeletal muscles
- Indirect-impulses from the brain stem to cause automatic movements that maintain skeletal muscle tone
What is in the dorsal/Posterior and ventral/anterior roots of the spinal chord?
Posterior root-composed of sensory axons lying between a spinal nerve and the dorsolateral aspect of spinal chord
Anterior root-composed of motor neurons that emerge from anterior aspect of spinal chord extends laterally to join posterior root forming a spinal nerve
What is a spinal nerve?
A dorsal and ventral nerve merged, mixed(sensory and motor)
What are dorsal/Posterior root ganglion?
group of cell bodies of sensory neurons and their supporting cell from posterior root spinal nerve
What are anterior median fissure and posterior median sulcus?
Anterior median fissure-wide groove on anterior side
Posterior median sulcus-narrow furrow on posterior side
What are gray matter and gray commissure?
Gray matter- shaped like an H or butterfly consists of cell body, unmeyilinated axons, dendrites and neuroglia
Gray commissure-forms crossbar of H connecting the gray matter on right and left sides
What is a central canal?
in center of gray commissure, passageway filled with cerebrospinal fluid that extends the length of the spinal chord
What are anterior and posterior gray horns?
Anterior gray horns-contain cell bodies of somatic motor neurons that provide impulse for skeletal muscle contractions
Posterior gray horns-contain inter neurons as well as axons of incoming sensory neurons
What is a Cauda Equina?
a collection of spinal nerve toots hang inferiorly from the spinal chord in vertebral column