5.3: Spinal Cord & Nerve Pathways

Spinal Cord

• Provides nerves that serve the limbs and trunk of the body

• consists of white (fatty wrapping) and grey matter (cell bodies)

Spinal cord anatomy:

• continous with caudal end of medulla

• Spans from cervical area to lumbar vertebrae at conus medullaris

• Individual spinal nerves below the caudal equina

What responses occur in the spinal cord

• Motor activation path

• Sensory Responses

• Spinal reflex sensory response ( dorsal root response)

How does the Motor activation response work?

• Upper motor neurons from the brain bring commands and synapse with lower motor neurons at the spinal cord to activate muscles

How does sensory response work?

For deep Kinesthetic senses and special senses

• involves sensory neurons transmitting to relat neurons into the CNS, which sends into to motor neurons for response

How does the spinal reflex sensory response work

• involuntary, quick response that only uses lower motor neurons

• Used for superficial somatic responses (pain, temp, touch) like withdrawal or reflex

Major Nerve Pathways