Physiology of the Spinal Cord

 

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The spinal cord sends and receives information from the entire body and brain (22). The information controls sensations, movement, and autonomic function . Nerves traveling through the body relay the information from the spinal cord to target cells in all areas of the body. Axon bundles travel through the body in 2 pathways: ascending and descending. The descending pathway, which controls voluntary movement, carries information from the corticospinal tract in the brain to the motor neurons in the spinal cord and then to the final destination in the body. Information carried by the ascending pathway from the sensory neurons in the spinal cord to the brain controls sensory information about body position, temperature, pain, and touch (18). Each level of the spinal cord corresponds to the sensory perception at a particular part of the body. The lower the level of the spinal cord, the lower the area of the body that is controlled by that level. Thus, the lower the level of the spinal cord injury, the lower the parts of the body that are affected by the injury.

Picture provided by The National Institutes of Health

The major pathways of the Spinal Cord: The ascending pathways (blue) carry sensory information from the body to the brain and spinal cord. The axons that comprise the ascending pathway end in the sensory cortex (blue) of the brain. The descending pathways (red) control motor function. The nerve cell bodies that control motor function are located in the motor cortex (red) of the brain.

 

Picture provided by The National Institutes of Health

Cross Section of the Spinal Cord

A. Descending (motor) pathways B. Ascending (sensory pathways) C. sensory neurons D. dorsal root ganglion (sensory) where the cell bodies of sensory neurons are located E. ventral root F. motor neurons (where axons descending from the motor cortex in the brain synapse with the cell bodies of spinal cord motor neurons.

 

Quick Facts
Cells of the Spinal Cord
Impulse Transmission

Anatomy of the Spinal Cord

Physiology of the Spinal Cord

Spinal Cord Injuries (Overview)

Types of Spinal Cord Injuries

The Body's Primary Response to a SCI
The Body's Secondary Response to a SCI

Effects of SCIs

Initial Treatment of SCIs
Recent Advances in SCI Research

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References